From 1d6d87e2bef1a0f0db78896abd1239708654783b Mon Sep 17 00:00:00 2001
From: Alexandre Teixeira <111787685+alteixeira20@users.noreply.github.com>
Date: Tue, 6 Oct 2026 03:16:54 +0100
Subject: [PATCH] fix(security): harden Python service boundaries

---
 mcp_servers/email_server.py                   |  19 +-
 routes/calendar_routes.py                     |   8 +-
 routes/chat_helpers.py                        |  12 +-
 routes/chat_routes.py                         |  22 +-
 routes/email/email_helpers.py                 | 169 +++++-
 routes/email/email_routes.py                  | 359 +++++++-----
 routes/hwfit_routes.py                        |   9 +-
 routes/search/search_routes.py                |  21 +-
 routes/session_routes.py                      |  10 +-
 routes/skills_routes.py                       |   9 +-
 routes/task/task_routes.py                    |   8 +-
 services/memory/memory_extractor.py           |  11 +-
 src/llm_core.py                               |  16 +-
 src/mail_attachment_paths.py                  |  32 ++
 src/readiness.py                              |  11 +-
 src/text_helpers.py                           |  14 +
 src/tools/calendar.py                         |  10 +-
 src/tools/notes.py                            |   2 +-
 src/upload_handler.py                         |  79 ++-
 src/url_safety.py                             |  49 ++
 .../test_calendar_reminder_minutes_parsing.py |  34 ++
 tests/test_codeql_python_residual_closure.py  | 522 ++++++++++++++++++
 tests/test_codeql_python_residual_followup.py | 260 +++++++++
 tests/test_codeql_python_residual_security.py | 164 ++++++
 tests/test_email_imap_timeout.py              |  12 +-
 tests/test_email_send_only_no_inbox.py        |   2 +-
 tests/test_email_smtp_security.py             |  18 +-
 tests/test_email_test_connection_oauth.py     |  24 +-
 tests/test_imap_leak_fixes.py                 |   2 +-
 tests/test_notes_reminder_temporal_redos.py   |  60 ++
 tests/test_redos_residual_python.py           | 183 ++++++
 tests/test_security_regressions.py            |   8 +-
 32 files changed, 1911 insertions(+), 248 deletions(-)
 create mode 100644 src/mail_attachment_paths.py
 create mode 100644 tests/test_codeql_python_residual_closure.py
 create mode 100644 tests/test_codeql_python_residual_followup.py
 create mode 100644 tests/test_codeql_python_residual_security.py
 create mode 100644 tests/test_notes_reminder_temporal_redos.py
 create mode 100644 tests/test_redos_residual_python.py

diff --git a/mcp_servers/email_server.py b/mcp_servers/email_server.py
index af1005ef3..ed8d5acff 100644
--- a/mcp_servers/email_server.py
+++ b/mcp_servers/email_server.py
@@ -3504,6 +3504,21 @@ def _block_sender(sender=None, uids=None, folder="INBOX", account=None, reason="
     }
 
 
+def _attachment_dir(folder, uid, account_id) -> Path:
+    """Owner/account-scoped extraction directory (see src.mail_attachment_paths).
+
+    `folder` comes from tool arguments and the IMAP server's own mailbox names
+    (`/` hierarchies, absolute or `..` segments), so it must not become a path;
+    the old `MAIL_ATTACHMENTS_DIR/{folder}_{uid}` wrote outside the root and
+    shared one directory between every owner's "INBOX 42".
+    """
+    from src.mail_attachment_paths import attachment_scope_dir
+
+    return attachment_scope_dir(
+        MAIL_ATTACHMENTS_DIR, folder, uid, owner=_current_owner(), account_id=account_id,
+    )
+
+
 def _download_attachment(uid, index, folder="INBOX", account=None):
     """Extract a specific attachment to disk and return its local path."""
     fixture = _fixture_attachment_source(uid, index, folder=folder, account=account)
@@ -3512,7 +3527,7 @@ def _download_attachment(uid, index, folder="INBOX", account=None):
         filename = str(att.get("filename") or f"attachment-{index}.txt")
         safe_name = re.sub(r"[^\w\s\-.]", "_", filename).strip() or f"attachment-{index}.txt"
         content = str(att.get("content") or "")
-        target_dir = Path(MAIL_ATTACHMENTS_DIR) / re.sub(r"[^A-Za-z0-9._-]", "_", f"{folder}_{uid}")
+        target_dir = _attachment_dir(folder, uid, _row.get("account_id") or account)
         path = target_dir / safe_name
         size = len(content.encode("utf-8"))
         try:
@@ -3545,7 +3560,7 @@ def _download_attachment(uid, index, folder="INBOX", account=None):
     raw = msg_data[0][1]
     msg = email.message_from_bytes(raw)
 
-    target_dir = Path(MAIL_ATTACHMENTS_DIR) / f"{folder}_{uid}"
+    target_dir = _attachment_dir(folder, uid, _load_config(account).get("account_id") or account)
     filepath = _extract_attachment_to_disk(msg, index, target_dir)
     if not filepath:
         return {"error": f"Attachment index {index} not found"}
diff --git a/routes/calendar_routes.py b/routes/calendar_routes.py
index ac7107ccb..aa84768fd 100644
--- a/routes/calendar_routes.py
+++ b/routes/calendar_routes.py
@@ -409,7 +409,7 @@ def parse_due_for_user(s: str) -> str:
     lower = s.lower().strip()
 
     def _parse_time(t):
-        t = _re.sub(r'\b([ap])\s*\.?\s*m\.?\b', r'\1m', t.strip(), flags=_re.IGNORECASE)
+        t = _re.sub(r'\b([ap])(?:\s*\.)?\s*m\.?\b', r'\1m', t.strip(), flags=_re.IGNORECASE)
         m = _re.match(r'^\s*(\d{1,2})(?::(\d{2}))?\s*(am|pm)?\s*$', t, _re.IGNORECASE)
         if not m: return None
         h = int(m.group(1)); mn = int(m.group(2) or 0); ampm = (m.group(3) or "").lower()
@@ -433,7 +433,7 @@ def parse_due_for_user(s: str) -> str:
             return base.replace(hour=t[0], minute=t[1]).isoformat()
 
     # Time-first: "3pm today", "11pm today", "9am tomorrow"
-    m = _re.match(r'^(.+?)\s+(today|tonight|tomorrow|tmrw|yesterday)$', lower)
+    m = _re.match(r'^(.*\S)\s+(today|tonight|tomorrow|tmrw|yesterday)$', lower)
     if m:
         time_part, word = m.group(1).strip(), m.group(2)
         base = today
@@ -530,7 +530,7 @@ def _parse_dt(s: str) -> datetime:
 
     def _parse_time(t: str):
         """Return (hour, minute) from '1pm', '1:30 PM', '13:00', etc., or None."""
-        t = _re.sub(r'\b([ap])\s*\.?\s*m\.?\b', r'\1m', t.strip(), flags=_re.IGNORECASE)
+        t = _re.sub(r'\b([ap])(?:\s*\.)?\s*m\.?\b', r'\1m', t.strip(), flags=_re.IGNORECASE)
         m = _re.match(r'^\s*(\d{1,2})(?::(\d{2}))?\s*(am|pm)?\s*$', t, _re.IGNORECASE)
         if not m:
             return None
@@ -562,7 +562,7 @@ def _parse_dt(s: str) -> datetime:
 
     # time-first: "3pm today", "9am tomorrow", "11pm tonight"
     # (parity with parse_due_for_user, which handles these via the same form)
-    m = _re.match(r'^(.+?)\s+(today|tonight|tomorrow|tmrw|yesterday)$', lower)
+    m = _re.match(r'^(.*\S)\s+(today|tonight|tomorrow|tmrw|yesterday)$', lower)
     if m:
         time_part, word = m.group(1).strip(), m.group(2)
         base = today
diff --git a/routes/chat_helpers.py b/routes/chat_helpers.py
index eb5fcf489..472128eaf 100644
--- a/routes/chat_helpers.py
+++ b/routes/chat_helpers.py
@@ -98,7 +98,9 @@ def clean_repeated_assistant_content(text: object) -> str:
         "",
         value,
     ).strip()
-    value = re.sub(r"(?is)\s*</\s*think\s*>\s*$", "", value).strip()
+    # No leading `\s*`: .strip() removes that whitespace anyway, and scanning
+    # it from every offset of a long whitespace run was quadratic (ReDoS).
+    value = re.sub(r"(?is)</\s*think\s*>\s*$", "", value).strip()
     return value
 
 _CASUAL_OPENING_RE = re.compile(
@@ -1324,13 +1326,17 @@ def _normalize_thinking(text: str) -> str:
 
     # Handle garbled <think> tags: reasoning text followed by <think> as separator
     # e.g. "The user said...I should respond.\n<think>Hey! What's up?"
+    # Linear form of `^([\s\S]+?)\n*<think>\s*([\s\S]*?)(?:</think>)?\s*$`:
+    # the lookbehind stops the lazy prefix re-scanning a newline run from every
+    # offset, and the optional trailing closer is dropped after the match
+    # instead of being retried at every body offset (both were quadratic).
     garbled = re.match(
-        r'^([\s\S]+?)\n*<think(?:ing)?>\s*([\s\S]*?)(?:</think(?:ing)?>)?\s*$',
+        r'^([\s\S]+?)(?<![\s\S]\n)\n*<think(?:ing)?>\s*([\s\S]*)$',
         text, re.IGNORECASE
     )
     if garbled:
         before = garbled.group(1).strip()
-        after = garbled.group(2).strip()
+        after = re.sub(r'</think(?:ing)?>$', '', garbled.group(2).rstrip(), flags=re.IGNORECASE).strip()
         # Only treat as garbled if the part before <think> looks like reasoning
         reasoning_starts = (
             'The user ', 'I need ', 'I should ', 'I will ',
diff --git a/routes/chat_routes.py b/routes/chat_routes.py
index 3bd0f01bf..e3f7bfa02 100644
--- a/routes/chat_routes.py
+++ b/routes/chat_routes.py
@@ -327,13 +327,31 @@ def _is_external_discovery_request(text: str) -> bool:
     ))
 
 
+_URL_SCHEME_RE = re.compile(r"https?://", re.I)
+_PDF_URL_TAIL_RE = re.compile(r"\.pdf\b|/pdf/", re.I)
+
+
+def _mentions_pdf_url(value: str) -> bool:
+    """Same as ``re.search(r"https?://[^\\s]+(?:\\.pdf\\b|/pdf/)", value, re.I)``.
+
+    Checked per whitespace-free token from its first scheme only (a later
+    scheme's tail is a suffix of the first's), so a token packed with
+    `http://` repeats is scanned once instead of once per repeat (ReDoS).
+    """
+    for token in value.split():
+        scheme = _URL_SCHEME_RE.search(token)
+        if scheme and _PDF_URL_TAIL_RE.search(token, scheme.end() + 1):
+            return True
+    return False
+
+
 def _prefers_structured_document_tools(text: str) -> bool:
     """Identify external paper/PDF extraction where shell is a bad source route."""
     value = str(text or "")
     if re.search(r"(?:^|\s)(?:file://)?/workspace/[^\s`\"']+\.pdf\b", value, re.I):
         return False
     return bool(
-        re.search(r"https?://[^\s]+(?:\.pdf\b|/pdf/)", value, re.I)
+        _mentions_pdf_url(value)
         or re.search(
             r"\b(?:paper|report|study)\b[\s\S]{0,1200}?"
             r"\b(?:tables?|figures?|benchmarks?|scores?|metrics?)\b",
@@ -2507,7 +2525,7 @@ def setup_chat_routes(
             _explicit_web_intent = (
                 _explicit_url_target
                 or bool(re.search(
-                r"\b(search|look\s+(?:this|that|it|them|these|those)?\s*up|lookup|find\s*out|google|browse|web|online|latest|current|today|news|weather|forecast|rate|exchange\s+rate)\b",
+                r"\b(search|look\s+(?:(?:this|that|it|them|these|those)\s*)?up|lookup|find\s*out|google|browse|web|online|latest|current|today|news|weather|forecast|rate|exchange\s+rate)\b",
                 _msg_l,
                 ))
                 or requires_external_web_verification(message)
diff --git a/routes/email/email_helpers.py b/routes/email/email_helpers.py
index 26ef3aa50..163132b85 100644
--- a/routes/email/email_helpers.py
+++ b/routes/email/email_helpers.py
@@ -17,6 +17,8 @@ import base64
 import time
 import imaplib
 import smtplib
+import socket
+import ssl
 import email as email_mod
 import email.header
 import email.utils
@@ -36,6 +38,7 @@ from typing import Optional, List
 
 from src.auth_helpers import _auth_disabled, get_current_user
 from src.secret_storage import decrypt as _decrypt
+from src.url_safety import OutboundAddressBlocked, connect_outbound_tcp
 
 logger = logging.getLogger(__name__)
 
@@ -160,6 +163,94 @@ def _smtp_security_mode(cfg: dict) -> str:
     return "ssl"
 
 
+# Raised when a mail host resolves into a denied range (see _mail_private_blocked).
+MailServerAddressBlocked = OutboundAddressBlocked
+
+
+def _mail_private_blocked(owner: str | None) -> bool:
+    """Whether private/loopback/shared mail destinations are denied for *owner*.
+
+    Link-local (cloud metadata), multicast, reserved and unspecified addresses
+    are always denied (src/url_safety.py). Private ranges are where a mail
+    tester or saved account becomes an internal-network probe, so they are
+    only allowed for an admin or in single-user mode (AUTH_ENABLED=false), the
+    same principals trusted with host-level tools. Operators of multi-user
+    deployments with a LAN mail server opt in with EMAIL_ALLOW_PRIVATE_IPS=true;
+    EMAIL_BLOCK_PRIVATE_IPS=true denies private ranges for everyone.
+    """
+    if os.getenv("EMAIL_BLOCK_PRIVATE_IPS", "").strip().lower() == "true":
+        return True
+    if os.getenv("EMAIL_ALLOW_PRIVATE_IPS", "").strip().lower() == "true":
+        return False
+    from src.tool_security import owner_is_admin_or_single_user
+
+    return not owner_is_admin_or_single_user((owner or "").strip() or None)
+
+
+def _mail_socket_timeout(timeout):
+    return socket._GLOBAL_DEFAULT_TIMEOUT if timeout is None else timeout
+
+
+class _PolicyIMAP4(imaplib.IMAP4):
+    """IMAP4 whose socket comes from connect_outbound_tcp.
+
+    The mail host is resolved once and connected to only at the addresses the
+    address policy approved, so DNS rebinding between check and connect is
+    impossible. STARTTLS still verifies against ``self.host``.
+    """
+
+    def __init__(self, host, port, *, block_private: bool, timeout=None):
+        self._block_private = block_private
+        super().__init__(host, port, timeout=timeout)
+
+    def _create_socket(self, timeout):
+        if timeout is not None and not timeout:
+            raise ValueError("Non-blocking socket (timeout=0) is not supported")
+        return connect_outbound_tcp(
+            self.host, self.port, timeout=_mail_socket_timeout(timeout), block_private=self._block_private,
+        )
+
+
+class _PolicyIMAP4_SSL(imaplib.IMAP4_SSL):
+    """IMAP4_SSL over a policy-checked socket; TLS SNI/verification use the hostname."""
+
+    def __init__(self, host, port, *, block_private: bool, timeout=None, ssl_context=None):
+        self._block_private = block_private
+        super().__init__(host, port, ssl_context=ssl_context, timeout=timeout)
+
+    def _create_socket(self, timeout):
+        sock = _PolicyIMAP4._create_socket(self, timeout)
+        return self.ssl_context.wrap_socket(sock, server_hostname=self.host)
+
+
+class _PolicySMTP(smtplib.SMTP):
+    """SMTP whose socket comes from connect_outbound_tcp (see _PolicyIMAP4)."""
+
+    def __init__(self, host="", port=0, *, block_private: bool, **kwargs):
+        self._block_private = block_private
+        super().__init__(host, port, **kwargs)
+
+    def _get_socket(self, host, port, timeout):
+        if timeout is not None and not timeout:
+            raise ValueError("Non-blocking socket (timeout=0) is not supported")
+        return connect_outbound_tcp(
+            host, port, timeout=timeout, block_private=self._block_private,
+            source_address=self.source_address,
+        )
+
+
+class _PolicySMTP_SSL(smtplib.SMTP_SSL):
+    """SMTP_SSL over a policy-checked socket; TLS SNI/verification use the hostname."""
+
+    def __init__(self, host="", port=0, *, block_private: bool, **kwargs):
+        self._block_private = block_private
+        super().__init__(host, port, **kwargs)
+
+    def _get_socket(self, host, port, timeout):
+        sock = _PolicySMTP._get_socket(self, host, port, timeout)
+        return self.context.wrap_socket(sock, server_hostname=self._host)
+
+
 def _send_smtp_message(cfg: dict, from_addr: str, recipients: list[str], message: str | bytes, timeout: int = 30) -> None:
     """Send through SMTP using the configured transport security mode."""
     host = cfg["smtp_host"]
@@ -178,14 +269,15 @@ def _send_smtp_message(cfg: dict, from_addr: str, recipients: list[str], message
             smtp.login(user, password)
 
     security = _smtp_security_mode(cfg)
+    block_private = _mail_private_blocked(cfg.get("owner"))
 
     if security == "ssl":
-        with smtplib.SMTP_SSL(host, port, timeout=timeout) as smtp:
+        with _PolicySMTP_SSL(host, port, timeout=timeout, block_private=block_private) as smtp:
             _auth_smtp(smtp)
             smtp.sendmail(from_addr, recipients, message)
         return
 
-    with smtplib.SMTP(host, port, timeout=timeout) as smtp:
+    with _PolicySMTP(host, port, timeout=timeout, block_private=block_private) as smtp:
         if security == "starttls":
             smtp.starttls()
         _auth_smtp(smtp)
@@ -224,6 +316,39 @@ def _friendly_email_auth_error(protocol: str, host: str, error: object) -> str:
     return raw[:200]
 
 
+# Bound at import: callers (and tests) may swap out imaplib.IMAP4 itself.
+_IMAP_ABORT = imaplib.IMAP4.abort
+
+
+def _mail_connection_test_error(protocol: str, host: str, error: BaseException) -> str:
+    """User-facing result for a failed IMAP/SMTP connection test.
+
+    Transport failures are reported by category, never with the peer's own
+    bytes: a non-mail service answering on the chosen host/port would
+    otherwise have its banner echoed back (an internal-service fingerprinting
+    oracle). Errors from a server that does speak the protocol (login/auth
+    rejections) keep their text via _friendly_email_auth_error, since that is
+    what the user needs to fix their settings.
+    """
+    if isinstance(error, MailServerAddressBlocked):
+        return f"{protocol} server address is not allowed by this server's network policy"
+    if isinstance(error, (_IMAP_ABORT, smtplib.SMTPConnectError, smtplib.SMTPServerDisconnected)):
+        return f"{protocol} server did not respond like an {protocol} server"
+    if isinstance(error, ssl.SSLCertVerificationError):
+        return f"{protocol} TLS certificate verification failed"
+    if isinstance(error, ssl.SSLError):
+        return f"{protocol} TLS handshake failed; check the port and security setting"
+    if isinstance(error, (socket.timeout, TimeoutError)):
+        return f"{protocol} connection timed out"
+    if isinstance(error, ConnectionRefusedError):
+        return f"{protocol} connection refused"
+    if isinstance(error, socket.gaierror):
+        return f"{protocol} server name could not be resolved"
+    if isinstance(error, OSError) and not isinstance(error, smtplib.SMTPException):
+        return f"{protocol} connection failed"
+    return _friendly_email_auth_error(protocol, host, error)
+
+
 def _strip_think(text: str) -> str:
     """Email-flavored think strip — thin wrapper over the central helper.
 
@@ -682,18 +807,21 @@ def _ensure_sender_signatures_table(conn):
         _lg.getLogger(__name__).warning(f"sender_signatures owner-migration skipped: {_mig_e}")
 
 
-def attachment_extract_dir(folder: str, uid: str) -> Path:
-    """Containment-safe extraction directory for an attachment.
+def attachment_extract_dir(folder: str, uid: str, *, owner: str, account_id: str | None) -> Path:
+    """Containment-safe extraction directory for one message's attachments.
 
-    `folder` and `uid` are user-controlled (query/path params). Flatten them to
-    a single safe path segment so a value like folder='../../tmp' can't escape
-    ATTACHMENTS_DIR, then assert containment as belt-and-suspenders."""
-    key = re.sub(r"[^A-Za-z0-9._-]", "_", f"{folder}_{uid}") or "_"
-    target = (ATTACHMENTS_DIR / key).resolve()
-    base = ATTACHMENTS_DIR.resolve()
-    if target != base and base not in target.parents:
+    IMAP UIDs are small per-mailbox counters, so `folder_uid` alone put every
+    user's and every account's "INBOX 42" in one directory, where extractions
+    overwrote each other by filename (a path handed to one user's agent could
+    then hold another user's attachment). See src.mail_attachment_paths: the
+    directory is keyed by (owner, account, folder, uid) and contained in
+    ATTACHMENTS_DIR whatever `folder`/`uid` hold."""
+    from src.mail_attachment_paths import attachment_scope_dir
+
+    try:
+        return attachment_scope_dir(ATTACHMENTS_DIR, folder, uid, owner=owner, account_id=account_id)
+    except ValueError:
         raise HTTPException(400, "Invalid attachment location")
-    return target
 
 
 def _init_scheduled_db():
@@ -1074,6 +1202,8 @@ def _get_email_config(account_id: str | None = None, owner: str = "") -> dict:
                 cfg = {
                     "account_id": row.id,
                     "account_name": row.name,
+                    # Principal for the outbound mail address policy.
+                    "owner": row.owner or owner or "",
                     "smtp_host": row.smtp_host or "",
                     "smtp_port": int(row.smtp_port or 465),
                     "smtp_security": _smtp_security_mode({"smtp_security": getattr(row, "smtp_security", ""), "smtp_port": row.smtp_port}),
@@ -1107,6 +1237,7 @@ def _get_email_config(account_id: str | None = None, owner: str = "") -> dict:
     cfg = {
         "account_id": resolved_id,
         "account_name": "legacy",
+        "owner": owner or "",
         "smtp_host": settings.get("smtp_host", os.environ.get("SMTP_HOST", "")),
         "smtp_port": int(settings.get("smtp_port", os.environ.get("SMTP_PORT", "465")) or 465),
         "smtp_security": _smtp_security_mode({
@@ -1170,11 +1301,16 @@ def _open_imap_connection(
     starttls: bool,
     timeout: int = _IMAP_TIMEOUT_SECONDS,
     ssl_context=None,
+    owner: str | None = None,
 ):
-    """Open an IMAP connection using the configured security mode."""
+    """Open an IMAP connection using the configured security mode.
+
+    `owner` is the principal the destination is judged for
+    (see _mail_private_blocked)."""
     port = int(port or 993)
+    block_private = _mail_private_blocked(owner)
     if starttls:
-        conn = imaplib.IMAP4(host, port, timeout=timeout)
+        conn = _PolicyIMAP4(host, port, timeout=timeout, block_private=block_private)
         try:
             if ssl_context:
                 conn.starttls(ssl_context=ssl_context)
@@ -1190,9 +1326,9 @@ def _open_imap_connection(
             raise
     elif port == 993:
         kwargs = {"ssl_context": ssl_context} if ssl_context else {}
-        conn = imaplib.IMAP4_SSL(host, port, timeout=timeout, **kwargs)
+        conn = _PolicyIMAP4_SSL(host, port, timeout=timeout, block_private=block_private, **kwargs)
     else:
-        conn = imaplib.IMAP4(host, port, timeout=timeout)
+        conn = _PolicyIMAP4(host, port, timeout=timeout, block_private=block_private)
     try:
         conn.sock.settimeout(timeout)
     except Exception:
@@ -1232,6 +1368,7 @@ def _imap_connect(account_id: str | None = None, owner: str = "",
         cfg["imap_port"],
         starttls=bool(cfg.get("imap_starttls")),
         timeout=timeout,
+        owner=cfg.get("owner"),
     )
     try:
         if cfg.get("oauth_provider") == "google":
diff --git a/routes/email/email_routes.py b/routes/email/email_routes.py
index e5b0d3224..0b71116d6 100644
--- a/routes/email/email_routes.py
+++ b/routes/email/email_routes.py
@@ -36,6 +36,7 @@ from pathlib import Path
 from email.mime.text import MIMEText
 from email.mime.multipart import MIMEMultipart
 
+from starlette.concurrency import run_in_threadpool
 from fastapi import APIRouter, Query, UploadFile, File, BackgroundTasks, HTTPException, Depends, Request
 from fastapi.responses import FileResponse, StreamingResponse
 from src.constants import DATA_DIR
@@ -60,6 +61,7 @@ from .email_helpers import (
     _fetch_sender_thread_context, _pre_retrieve_context,
     _EMAIL_REPLY_SYS_PROMPT_BASE, _POOL_HOOKS,
     _friendly_email_auth_error, _email_summary_failure_log_detail,
+    _mail_connection_test_error, _mail_private_blocked, _PolicySMTP, _PolicySMTP_SSL,
     _generate_email_summary, EMAIL_SUMMARY_ERROR_CODE, EMAIL_SUMMARY_ERROR_MESSAGE,
     SendEmailRequest, ExtractStyleRequest,
     ATTACHMENTS_DIR, COMPOSE_UPLOADS_DIR, SCHEDULED_DB,
@@ -1523,6 +1525,44 @@ def _envelope_recipients(*fields: str) -> list:
     return out
 
 
+_MD_LINK_URL_RE = re.compile(r"\((https?://)[^)\s]*")
+
+
+def _md_links_to_html(s: str) -> str:
+    """Linear ``re.sub(r"\\[([^\\]]+)\\]\\((https?://[^)\\s]+)\\)", '<a href="\\2">\\1</a>', s)``.
+
+    Every `[` before the next `]` shares that `]`, so only the first can match;
+    and when a URL runs into whitespace/end without `)`, every later `[` whose
+    `]` also lies before that stop fails the same way. Skipping those spans
+    keeps a `[[[` or `[a](http://x[a](http://x` flood O(n) instead of the
+    regex's O(n^2).
+    """
+    out: list[str] = []
+    emitted = scan = 0
+    while True:
+        open_at = s.find("[", scan)
+        if open_at < 0:
+            break
+        close_at = s.find("]", open_at + 1)
+        if close_at < 0:
+            break
+        scan = close_at + 1
+        if close_at == open_at + 1:
+            continue
+        url = _MD_LINK_URL_RE.match(s, close_at + 1)
+        if url is None:
+            continue
+        end = url.end()
+        if end < len(s) and s[end] == ")" and end > url.end(1):
+            out.append(s[emitted:open_at])
+            out.append(f'<a href="{s[url.start(1):end]}">{s[open_at + 1:close_at]}</a>')
+            emitted = scan = end + 1
+        elif end > url.end(1):
+            scan = max(scan, s.rfind("]", scan, end) + 1)
+    out.append(s[emitted:])
+    return "".join(out)
+
+
 def _md_to_email_html(text: str) -> str:
     """Render the compose markdown body to a SAFE HTML fragment for the email's
     text/html part. Everything is HTML-escaped FIRST (so a pasted <script> /
@@ -1538,7 +1578,7 @@ def _md_to_email_html(text: str) -> str:
         s = re.sub(r"~~([^~]+)~~", r"<del>\1</del>", s)
         s = re.sub(r"`([^`]+)`", r"<code>\1</code>", s)
         # links: text + http(s) url only (escape() already neutralised quotes)
-        s = re.sub(r"\[([^\]]+)\]\((https?://[^)\s]+)\)", r'<a href="\2">\1</a>', s)
+        s = _md_links_to_html(s)
         return s
 
     parts: list[str] = []
@@ -3900,7 +3940,7 @@ def setup_email_routes():
             _row, att = fixture_att
             filename = str(att.get("filename") or f"attachment-{index}.txt")
             safe_name = re.sub(r"[^\w\s\-.]", "_", filename).strip() or f"attachment-{index}.txt"
-            target_dir = attachment_extract_dir(folder, uid)
+            target_dir = attachment_extract_dir(folder, uid, owner=owner, account_id=account_id)
             target_dir.mkdir(parents=True, exist_ok=True)
             filepath = target_dir / safe_name
             filepath.write_bytes(str(att.get("content") or "").encode("utf-8"))
@@ -3919,7 +3959,7 @@ def setup_email_routes():
             msg = email_mod.message_from_bytes(raw)
 
             # Extract to a per-email folder
-            target_dir = attachment_extract_dir(folder, uid)
+            target_dir = attachment_extract_dir(folder, uid, owner=owner, account_id=account_id)
             filepath = _extract_attachment_to_disk(msg, index, target_dir)
             if not filepath:
                 return {"error": f"Attachment index {index} not found"}
@@ -3951,7 +3991,7 @@ def setup_email_routes():
             if not attachments:
                 raise HTTPException(status_code=404, detail="No downloadable attachments")
 
-            target_dir = attachment_extract_dir(folder, uid)
+            target_dir = attachment_extract_dir(folder, uid, owner=owner, account_id=account_id)
             zip_buf = io.BytesIO()
             used_names: dict[str, int] = {}
             with zipfile.ZipFile(zip_buf, "w", compression=zipfile.ZIP_DEFLATED) as zf:
@@ -4091,7 +4131,7 @@ def setup_email_routes():
                                     att for att in _list_attachments_from_msg(msg)
                                     if not _is_likely_signature_image_attachment(att)
                                 ]
-                                target_dir = attachment_extract_dir(folder, uid)
+                                target_dir = attachment_extract_dir(folder, uid, owner=owner, account_id=acct)
                                 for att in attachments:
                                     idx = att.get("index")
                                     if idx is None:
@@ -4156,7 +4196,7 @@ def setup_email_routes():
                     continue
                 if not ct.lower().startswith("image/"):
                     raise HTTPException(status_code=415, detail="Content-ID is not an image")
-                target_dir = attachment_extract_dir(folder, uid)
+                target_dir = attachment_extract_dir(folder, uid, owner=owner, account_id=account_id)
                 filepath = _extract_attachment_to_disk(msg, idx, target_dir)
                 if not filepath:
                     raise HTTPException(status_code=404, detail="Inline image not found")
@@ -4194,7 +4234,7 @@ def setup_email_routes():
             raw = msg_data[0][1]
             msg = email_mod.message_from_bytes(raw)
 
-            target_dir = attachment_extract_dir(folder, uid)
+            target_dir = attachment_extract_dir(folder, uid, owner=owner, account_id=account_id)
             filepath = _extract_attachment_to_disk(msg, index, target_dir)
             if not filepath:
                 return {"error": f"Attachment index {index} not found"}
@@ -4522,7 +4562,9 @@ def setup_email_routes():
                 try:
                     content = filepath.read_text(encoding="utf-8", errors="replace")
                 except Exception as e:
-                    return {"error": f"Failed to read text file: {e}", "filename": base}
+                    # OSError text includes the server-side extraction path.
+                    logger.warning("Failed to read text attachment %s: %s", base, e)
+                    return {"error": "Failed to read text file", "filename": base}
                 doc_id = _create_markdown_doc(content, "Imported from email attachment")
                 return {"doc_id": doc_id, "filename": filepath.name}
 
@@ -4539,7 +4581,7 @@ def setup_email_routes():
             _row, att = fixture_att
             filename = str(att.get("filename") or f"attachment-{index}.txt")
             safe_name = re.sub(r"[^\w\s\-.]", "_", filename).strip() or f"attachment-{index}.txt"
-            target_dir = attachment_extract_dir(folder, uid)
+            target_dir = attachment_extract_dir(folder, uid, owner=owner, account_id=account_id)
             target_dir.mkdir(parents=True, exist_ok=True)
             filepath = target_dir / safe_name
             filepath.write_bytes(str(att.get("content") or "").encode("utf-8"))
@@ -4553,7 +4595,7 @@ def setup_email_routes():
             raw = msg_data[0][1]
             msg = email_mod.message_from_bytes(raw)
 
-            target_dir = attachment_extract_dir(folder, uid)
+            target_dir = attachment_extract_dir(folder, uid, owner=owner, account_id=account_id)
             filepath = _extract_attachment_to_disk(msg, index, target_dir)
             if not filepath:
                 return {"error": f"Attachment index {index} not found"}
@@ -5162,7 +5204,7 @@ def setup_email_routes():
                 return {"success": False, "error": "Email not found"}
             raw = msg_data[0][1]
             msg = email_mod.message_from_bytes(raw)
-            target_dir = attachment_extract_dir(folder, uid)
+            target_dir = attachment_extract_dir(folder, uid, owner=owner, account_id=account_id)
             filepath = _extract_attachment_to_disk(msg, index, target_dir)
             if not filepath:
                 return {"success": False, "error": f"Attachment index {index} not found"}
@@ -6860,6 +6902,158 @@ def setup_email_routes():
         finally:
             db.close()
 
+    def _test_mail_connections(body: dict, owner: str) -> dict:
+        """Blocking IMAP/SMTP connection test for /accounts/test.
+
+        Runs in the threadpool: each probe can block for its full socket
+        timeout, which on the event loop stalled every other request. The
+        connections go through the outbound mail address policy for `owner`
+        (the user who chose the hosts)."""
+        imap_result = {"ok": False}
+        smtp_result = None
+
+        imap_host = (body.get("imap_host") or "").strip()
+        imap_port, imap_port_err = _coerce_port(body.get("imap_port"), 993)
+        imap_user = (body.get("imap_user") or "").strip()
+        imap_pass = body.get("imap_password") or ""
+        imap_starttls = bool(body.get("imap_starttls"))
+        oauth_provider = body.get("oauth_provider") or ""
+
+        google_token = None
+        google_token_loaded = False
+        google_ssl_context = (
+            ssl.create_default_context()
+            if oauth_provider == "google"
+            else None
+        )
+
+        def _google_token():
+            nonlocal google_token, google_token_loaded
+            if not google_token_loaded:
+                google_token = _get_valid_google_token(body.get("account_id"), body)
+                google_token_loaded = True
+            if not google_token:
+                raise RuntimeError("Google OAuth token unavailable — reconnect the account")
+            return google_token
+
+        if imap_port_err:
+            imap_result = {"ok": False, "error": imap_port_err}
+        elif not (imap_host and imap_user and (imap_pass or oauth_provider == "google")):
+            imap_result = {"ok": False, "error": "Need IMAP host, username, and password"}
+        elif oauth_provider == "google" and _normalized_mail_host(imap_host) != _GOOGLE_OAUTH_IMAP_HOST:
+            imap_result = {"ok": False, "error": "Google OAuth IMAP requires imap.gmail.com"}
+        elif oauth_provider == "google" and not _google_oauth_imap_transport_allowed(imap_port, imap_starttls):
+            imap_result = {"ok": False, "error": "Google OAuth IMAP requires TLS on port 993 or STARTTLS on port 143"}
+        else:
+            # Connection mode resolution:
+            #   STARTTLS on  → plain IMAP4 + .starttls() (upgrade)
+            #   STARTTLS off + port 993 → IMAP4_SSL (implicit SSL, "IMAPS")
+            #   STARTTLS off + any other port → plain IMAP4 (no encryption)
+            # Without the last branch, local servers exposed on a non-993
+            # port (Dovecot on 31143, etc.) would always fail the SSL
+            # handshake because they're not actually wrapped in TLS.
+            try:
+                imap_kwargs = {
+                    "starttls": imap_starttls,
+                    "timeout": _IMAP_TIMEOUT_SECONDS,
+                    "owner": owner,
+                }
+                if google_ssl_context:
+                    imap_kwargs["ssl_context"] = google_ssl_context
+                conn = _open_imap_connection(
+                    imap_host,
+                    imap_port,
+                    **imap_kwargs,
+                )
+                try:
+                    if oauth_provider == "google":
+                        token = _google_token()
+                        conn.authenticate("XOAUTH2", lambda x: _xoauth2_bytes(imap_user, token))
+                    else:
+                        conn.login(imap_user, imap_pass)
+                    imap_result = {"ok": True}
+                finally:
+                    try: conn.logout()
+                    except Exception: pass
+            except Exception as e:
+                imap_result = {"ok": False, "error": _mail_connection_test_error("IMAP", imap_host, e)}
+
+        smtp_host = (body.get("smtp_host") or "").strip()
+        smtp_port, smtp_port_err = _coerce_port(body.get("smtp_port"), 465)
+        if smtp_host and smtp_port_err:
+            smtp_result = {"ok": False, "error": smtp_port_err}
+        elif oauth_provider == "google" and smtp_host and _normalized_mail_host(smtp_host) != _GOOGLE_OAUTH_SMTP_HOST:
+            smtp_result = {"ok": False, "error": "Google OAuth SMTP requires smtp.gmail.com"}
+        elif (
+            oauth_provider == "google"
+            and smtp_host
+            and not _google_oauth_smtp_transport_allowed(
+                smtp_port,
+                _smtp_security_mode({"smtp_security": body.get("smtp_security"), "smtp_port": smtp_port}),
+            )
+        ):
+            smtp_result = {"ok": False, "error": "Google OAuth SMTP requires TLS on port 465 or STARTTLS on port 587"}
+        elif smtp_host:
+            smtp_security = _smtp_security_mode({"smtp_security": body.get("smtp_security"), "smtp_port": smtp_port})
+            smtp_user = (body.get("smtp_user") or imap_user).strip()
+            smtp_pass = body.get("smtp_password") or imap_pass
+            smtp = None
+            try:
+                if smtp_security == "ssl":
+                    smtp_kwargs = (
+                        {"context": google_ssl_context}
+                        if google_ssl_context
+                        else {}
+                    )
+                    smtp = _PolicySMTP_SSL(
+                        smtp_host,
+                        smtp_port,
+                        timeout=10,
+                        block_private=_mail_private_blocked(owner),
+                        **smtp_kwargs,
+                    )
+                else:
+                    smtp = _PolicySMTP(smtp_host, smtp_port, timeout=10, block_private=_mail_private_blocked(owner))
+                    if smtp_security == "starttls":
+                        try:
+                            if google_ssl_context:
+                                smtp.starttls(context=google_ssl_context)
+                            else:
+                                smtp.starttls()
+                        except Exception:
+                            # STARTTLS failed before the auth cleanup block.
+                            # Close the still-open plaintext socket explicitly.
+                            try:
+                                smtp.close()
+                            except Exception:
+                                pass
+                            smtp = None
+                            raise
+                if oauth_provider == "google":
+                    token = _google_token()
+                    smtp.ehlo()
+                    smtp.auth("XOAUTH2", lambda challenge=None: _xoauth2_raw(smtp_user, token), initial_response_ok=True)
+                else:
+                    smtp.login(smtp_user, smtp_pass)
+                smtp_result = {"ok": True}
+            except Exception as e:
+                smtp_result = {"ok": False, "error": _mail_connection_test_error("SMTP", smtp_host, e)}
+            finally:
+                if smtp is not None:
+                    try:
+                        smtp.quit()
+                    except Exception:
+                        try:
+                            smtp.close()
+                        except Exception:
+                            pass
+
+        return {
+            "ok": imap_result["ok"] and (smtp_result is None or smtp_result["ok"]),
+            "imap": imap_result,
+            "smtp": smtp_result,
+        }
+
     @router.post("/accounts/test")
     async def test_account_config(req: Request, owner: str = Depends(require_user)):
         """Try to actually connect to the provided IMAP (and optionally SMTP)
@@ -6923,148 +7117,7 @@ def setup_email_routes():
             # inline test payloads select the OAuth branch or supply token data.
             body = {key: value for key, value in body.items() if key not in _SERVER_OWNED_OAUTH_FIELDS}
 
-        imap_result = {"ok": False}
-        smtp_result = None
-
-        imap_host = (body.get("imap_host") or "").strip()
-        imap_port, imap_port_err = _coerce_port(body.get("imap_port"), 993)
-        imap_user = (body.get("imap_user") or "").strip()
-        imap_pass = body.get("imap_password") or ""
-        imap_starttls = bool(body.get("imap_starttls"))
-        oauth_provider = body.get("oauth_provider") or ""
-
-        google_token = None
-        google_token_loaded = False
-        google_ssl_context = (
-            ssl.create_default_context()
-            if oauth_provider == "google"
-            else None
-        )
-
-        def _google_token():
-            nonlocal google_token, google_token_loaded
-            if not google_token_loaded:
-                google_token = _get_valid_google_token(body.get("account_id"), body)
-                google_token_loaded = True
-            if not google_token:
-                raise RuntimeError("Google OAuth token unavailable — reconnect the account")
-            return google_token
-
-        if imap_port_err:
-            imap_result = {"ok": False, "error": imap_port_err}
-        elif not (imap_host and imap_user and (imap_pass or oauth_provider == "google")):
-            imap_result = {"ok": False, "error": "Need IMAP host, username, and password"}
-        elif oauth_provider == "google" and _normalized_mail_host(imap_host) != _GOOGLE_OAUTH_IMAP_HOST:
-            imap_result = {"ok": False, "error": "Google OAuth IMAP requires imap.gmail.com"}
-        elif oauth_provider == "google" and not _google_oauth_imap_transport_allowed(imap_port, imap_starttls):
-            imap_result = {"ok": False, "error": "Google OAuth IMAP requires TLS on port 993 or STARTTLS on port 143"}
-        else:
-            # Connection mode resolution:
-            #   STARTTLS on  → plain IMAP4 + .starttls() (upgrade)
-            #   STARTTLS off + port 993 → IMAP4_SSL (implicit SSL, "IMAPS")
-            #   STARTTLS off + any other port → plain IMAP4 (no encryption)
-            # Without the last branch, local servers exposed on a non-993
-            # port (Dovecot on 31143, etc.) would always fail the SSL
-            # handshake because they're not actually wrapped in TLS.
-            try:
-                imap_kwargs = {
-                    "starttls": imap_starttls,
-                    "timeout": _IMAP_TIMEOUT_SECONDS,
-                }
-                if google_ssl_context:
-                    imap_kwargs["ssl_context"] = google_ssl_context
-                conn = _open_imap_connection(
-                    imap_host,
-                    imap_port,
-                    **imap_kwargs,
-                )
-                try:
-                    if oauth_provider == "google":
-                        token = _google_token()
-                        conn.authenticate("XOAUTH2", lambda x: _xoauth2_bytes(imap_user, token))
-                    else:
-                        conn.login(imap_user, imap_pass)
-                    imap_result = {"ok": True}
-                finally:
-                    try: conn.logout()
-                    except Exception: pass
-            except Exception as e:
-                imap_result = {"ok": False, "error": _friendly_email_auth_error("IMAP", imap_host, e)}
-
-        smtp_host = (body.get("smtp_host") or "").strip()
-        smtp_port, smtp_port_err = _coerce_port(body.get("smtp_port"), 465)
-        if smtp_host and smtp_port_err:
-            smtp_result = {"ok": False, "error": smtp_port_err}
-        elif oauth_provider == "google" and smtp_host and _normalized_mail_host(smtp_host) != _GOOGLE_OAUTH_SMTP_HOST:
-            smtp_result = {"ok": False, "error": "Google OAuth SMTP requires smtp.gmail.com"}
-        elif (
-            oauth_provider == "google"
-            and smtp_host
-            and not _google_oauth_smtp_transport_allowed(
-                smtp_port,
-                _smtp_security_mode({"smtp_security": body.get("smtp_security"), "smtp_port": smtp_port}),
-            )
-        ):
-            smtp_result = {"ok": False, "error": "Google OAuth SMTP requires TLS on port 465 or STARTTLS on port 587"}
-        elif smtp_host:
-            smtp_security = _smtp_security_mode({"smtp_security": body.get("smtp_security"), "smtp_port": smtp_port})
-            smtp_user = (body.get("smtp_user") or imap_user).strip()
-            smtp_pass = body.get("smtp_password") or imap_pass
-            smtp = None
-            try:
-                if smtp_security == "ssl":
-                    smtp_kwargs = (
-                        {"context": google_ssl_context}
-                        if google_ssl_context
-                        else {}
-                    )
-                    smtp = smtplib.SMTP_SSL(
-                        smtp_host,
-                        smtp_port,
-                        timeout=10,
-                        **smtp_kwargs,
-                    )
-                else:
-                    smtp = smtplib.SMTP(smtp_host, smtp_port, timeout=10)
-                    if smtp_security == "starttls":
-                        try:
-                            if google_ssl_context:
-                                smtp.starttls(context=google_ssl_context)
-                            else:
-                                smtp.starttls()
-                        except Exception:
-                            # STARTTLS failed before the auth cleanup block.
-                            # Close the still-open plaintext socket explicitly.
-                            try:
-                                smtp.close()
-                            except Exception:
-                                pass
-                            smtp = None
-                            raise
-                if oauth_provider == "google":
-                    token = _google_token()
-                    smtp.ehlo()
-                    smtp.auth("XOAUTH2", lambda challenge=None: _xoauth2_raw(smtp_user, token), initial_response_ok=True)
-                else:
-                    smtp.login(smtp_user, smtp_pass)
-                smtp_result = {"ok": True}
-            except Exception as e:
-                smtp_result = {"ok": False, "error": _friendly_email_auth_error("SMTP", smtp_host, e)}
-            finally:
-                if smtp is not None:
-                    try:
-                        smtp.quit()
-                    except Exception:
-                        try:
-                            smtp.close()
-                        except Exception:
-                            pass
-
-        return {
-            "ok": imap_result["ok"] and (smtp_result is None or smtp_result["ok"]),
-            "imap": imap_result,
-            "smtp": smtp_result,
-        }
+        return await run_in_threadpool(_test_mail_connections, body, owner)
 
     @router.post("/accounts/{account_id}/set-default")
     async def set_default_account(account_id: str, owner: str = Depends(require_user)):
diff --git a/routes/hwfit_routes.py b/routes/hwfit_routes.py
index 960ebb025..c101ae78c 100644
--- a/routes/hwfit_routes.py
+++ b/routes/hwfit_routes.py
@@ -5,8 +5,9 @@ import shlex
 import subprocess
 from copy import deepcopy
 
-from fastapi import APIRouter, HTTPException
+from fastapi import APIRouter, Depends, HTTPException
 
+from core.middleware import require_admin
 from core.platform_compat import run_ssh_command
 from routes._validators import validate_remote_host, validate_ssh_port
 
@@ -198,7 +199,11 @@ def _inspect_model_path(model_path: str, host: str = "", ssh_port: str = "") ->
 
 
 def setup_hwfit_routes():
-    router = APIRouter(prefix="/api/hwfit", tags=["hwfit"])
+    # Admin-gated like the Cookbook routes this backs (/api/cookbook/gpus does
+    # the same SSH host probing): `host`/`ssh_port` make the server SSH out with
+    # its own key to any syntactically valid host, and `model_path` probes the
+    # host filesystem. Single-user mode and internal tool calls still pass.
+    router = APIRouter(prefix="/api/hwfit", tags=["hwfit"], dependencies=[Depends(require_admin)])
 
     @router.get("/system")
     def get_system(host: str = "", ssh_port: str = "", platform: str = "", fresh: bool = False):
diff --git a/routes/search/search_routes.py b/routes/search/search_routes.py
index 5aafa03cb..a63607649 100644
--- a/routes/search/search_routes.py
+++ b/routes/search/search_routes.py
@@ -43,11 +43,22 @@ def setup_search_routes(config) -> APIRouter:
     router = APIRouter(tags=["search"])
 
     @router.get("/search/web", response_class=HTMLResponse)
-    async def web_search_page(q: str = Query("", min_length=0)) -> HTMLResponse:
+    async def web_search_page(request: Request, q: str = Query("", min_length=0)) -> HTMLResponse:
         """Browser-facing search results page for clickable agent web_search rows."""
+        # The site CSP allows inline script only with the per-request nonce
+        # (SecurityHeadersMiddleware); without it this page's script never ran.
+        nonce = html.escape(getattr(request.state, "csp_nonce", "") or "", quote=True)
         safe_q = str(q or "").strip()
         title = html.escape(safe_q or "Web search")
-        q_json = json.dumps(safe_q)
+        # json.dumps leaves `<`, `>` and `&` alone, so q=</script><script ...>
+        # would close this inline <script> and inject markup (reflected XSS).
+        # Unicode-escape them; the JS string value is unchanged.
+        q_json = (
+            json.dumps(safe_q)
+            .replace("<", "\\u003c")
+            .replace(">", "\\u003e")
+            .replace("&", "\\u0026")
+        )
         page = f"""<!doctype html>
 <html>
 <head>
@@ -79,7 +90,7 @@ def setup_search_routes(config) -> APIRouter:
     <div class="status" id="status">Loading...</div>
     <div id="results"></div>
   </main>
-  <script>
+  <script nonce="{nonce}">
     const initialQuery = {q_json};
     const input = document.getElementById('query');
     const statusEl = document.getElementById('status');
@@ -103,7 +114,9 @@ def setup_search_routes(config) -> APIRouter:
       }}
       statusEl.textContent = sources.length ? `${{sources.length}} results` : 'No results';
       resultsEl.innerHTML = sources.map(s => {{
-        const url = s.url || s.link || '';
+        const rawUrl = String(s.url || s.link || '');
+        // Result URLs come from third-party search results: only http(s) may become a link.
+        const url = /^https?:[/][/]/i.test(rawUrl) ? rawUrl : '';
         const title = s.title || url || 'Untitled';
         const snippet = s.snippet || s.content || '';
         return `<a class="result" href="${{esc(url)}}" target="_blank" rel="noopener noreferrer">
diff --git a/routes/session_routes.py b/routes/session_routes.py
index 1807a8a58..fa687ee14 100644
--- a/routes/session_routes.py
+++ b/routes/session_routes.py
@@ -1601,7 +1601,13 @@ def setup_session_routes(
             raise HTTPException(404, "Session not found")
         skills = _context_info_skill_inventory(skills_manager, owner=owner)
         tools = _context_info_tool_inventory()
-        agents_md = _context_info_agents_md_inventory(cwd)
+        # `cwd` is caller-chosen. Walking it for AGENTS.md and reporting whether
+        # it exists confirms paths on the host, which /api/workspace/browse and
+        # /vet reserve for admins (or single-user mode); keep that boundary here.
+        from src.tool_security import owner_is_admin_or_single_user
+
+        _host_paths_visible = owner_is_admin_or_single_user(owner)
+        agents_md = _context_info_agents_md_inventory(cwd) if _host_paths_visible else []
         # Workspace visibility: lets the TUI answer "can the backend actually
         # see this directory?" (mounted vs bridge-only) without probing.
         from src.workspace_paths import backend_workspace_path, workspace_mount_pairs
@@ -1626,7 +1632,7 @@ def setup_session_routes(
         }
         _workspace = {
             "backend_path": _backend_cwd,
-            "exists_in_backend": bool(_backend_cwd) and Path(_backend_cwd).is_dir(),
+            "exists_in_backend": _host_paths_visible and bool(_backend_cwd) and Path(_backend_cwd).is_dir(),
             "mount_configured": bool(workspace_mount_pairs()),
             "via_mount": bool(_raw_cwd) and backend_workspace_path(_raw_cwd) != _raw_cwd,
         }
diff --git a/routes/skills_routes.py b/routes/skills_routes.py
index 87d8cb435..33b55e3c2 100644
--- a/routes/skills_routes.py
+++ b/routes/skills_routes.py
@@ -19,6 +19,7 @@ from pydantic import BaseModel, Field
 from services.memory.skills import SkillsManager
 from src.auth_helpers import get_current_user
 from src.prompt_security import untrusted_context_message
+from src.text_helpers import strip_closed_think_blocks
 from core.middleware import require_admin
 
 logger = logging.getLogger(__name__)
@@ -250,7 +251,7 @@ async def _eval_skill_run(skill_md: str, task: str, transcript: str,
         # Strip closed think blocks. If a <think> was opened but never closed
         # (the model ran out of budget mid-reasoning), drop everything from it
         # onward so its stray braces don't poison JSON extraction.
-        text = _re.sub(r'<think(?:ing)?>[\s\S]*?</think(?:ing)?>', '', text, flags=_re.I)
+        text = strip_closed_think_blocks(text)
         text = _re.sub(r'<think(?:ing)?>[\s\S]*$', '', text, flags=_re.I).strip()
 
         def _coerce(d):
@@ -403,7 +404,7 @@ async def _eval_skill_necessity(skill_md: str, others: list, url: str, model: st
     except Exception as e:
         logger.warning(f"Necessity check failed: {e}")
         return None
-    text = _re.sub(r'<think(?:ing)?>[\s\S]*?</think(?:ing)?>', '', (raw or ''), flags=_re.I)
+    text = strip_closed_think_blocks(raw or '')
     text = _re.sub(r'<think(?:ing)?>[\s\S]*$', '', text, flags=_re.I).strip()
     data = None
     a, b = text.find('{'), text.rfind('}')
@@ -493,7 +494,7 @@ async def _eval_skill_retrieval_precision(skill_md: str, others: list,
     except Exception as e:
         logger.warning(f"Retrieval precision check failed: {e}")
         return None
-    text = _re.sub(r'<think(?:ing)?>[\s\S]*?</think(?:ing)?>', '', (raw or ''), flags=_re.I)
+    text = strip_closed_think_blocks(raw or '')
     text = _re.sub(r'<think(?:ing)?>[\s\S]*$', '', text, flags=_re.I).strip()
     data = None
     a, b = text.find('{'), text.rfind('}')
@@ -1188,7 +1189,7 @@ async def _improve_skill_md(skill_md: str, verdict: dict, transcript: str, url,
     except Exception as e:
         logger.warning(f"Audit: improve call failed: {e}")
         return None
-    text = _re.sub(r'<think(?:ing)?>[\s\S]*?</think(?:ing)?>', '', (raw or ''), flags=_re.I)
+    text = strip_closed_think_blocks(raw or '')
     text = _re.sub(r'<think(?:ing)?>[\s\S]*$', '', text, flags=_re.I)
     text = _re.sub(r'</think(?:ing)?>', '', text, flags=_re.I).strip()
     if text.startswith("```"):
diff --git a/routes/task/task_routes.py b/routes/task/task_routes.py
index a1179d50e..49f65b313 100644
--- a/routes/task/task_routes.py
+++ b/routes/task/task_routes.py
@@ -1252,8 +1252,14 @@ def setup_task_routes(task_scheduler) -> APIRouter:
             if not out.get("prompt"):
                 return {"success": False, "message": "Could not extract a task instruction"}
             return {"success": True, "draft": out}
+        except HTTPException as e:
+            # llm_core raises HTTPException with curated upstream text.
+            logger.error(f"parse_task failed: {e.detail}")
+            return {"success": False, "message": str(e.detail)}
         except Exception as e:
+            # Anything else (JSON/parse/runtime errors) can carry internals;
+            # log it and keep the client message generic.
             logger.error(f"parse_task failed: {e}")
-            return {"success": False, "message": str(e)}
+            return {"success": False, "message": f"Could not draft a task ({type(e).__name__})"}
 
     return router
diff --git a/services/memory/memory_extractor.py b/services/memory/memory_extractor.py
index a1d1a19db..7d056cb40 100644
--- a/services/memory/memory_extractor.py
+++ b/services/memory/memory_extractor.py
@@ -610,7 +610,9 @@ async def update_persona_memory(
         )
 
         updated = strip_think(str(raw or ""), prose=True, prompt_echo=True).strip()
-        updated = re.sub(r"^```(?:text|markdown)?\s*|\s*```$", "", updated, flags=re.I | re.S).strip()
+        # No leading `\s*` before the closing fence: .strip() drops that
+        # whitespace anyway, and scanning it from every offset was quadratic.
+        updated = re.sub(r"^```(?:text|markdown)?\s*|```$", "", updated, flags=re.I | re.S).strip()
         if len(updated) > 6000:
             updated = updated[:6000].rstrip()
         if updated == existing_memory:
@@ -694,8 +696,9 @@ async def audit_memories(
         # Parse the JSON list, tolerating reasoning-model noise: <think> blocks,
         # markdown fences, leading prose, and trailing commas.
         import re as _re
+        from src.text_helpers import strip_closed_think_blocks
         text = (raw or "").strip()
-        text = _re.sub(r'<think(?:ing)?>[\s\S]*?</think(?:ing)?>', '', text, flags=_re.I).strip()
+        text = strip_closed_think_blocks(text).strip()
 
         def _loads_list(s):
             if not s:
@@ -711,7 +714,9 @@ async def audit_memories(
 
         cleaned = _loads_list(text)
         if cleaned is None:
-            _m = _re.search(r'```(?:json)?\s*\n?([\s\S]*?)```', text)
+            # Possessive `\s*+`: handing fence whitespace back to the body on a
+            # missing closing fence only rescanned the same tail (ReDoS).
+            _m = _re.search(r'```(?:json)?\s*+\n?([\s\S]*?)```', text)
             if _m:
                 cleaned = _loads_list(_m.group(1).strip())
         if cleaned is None:
diff --git a/src/llm_core.py b/src/llm_core.py
index 0908b56bb..bdd3a6a44 100644
--- a/src/llm_core.py
+++ b/src/llm_core.py
@@ -3249,7 +3249,7 @@ async def _stream_llm_inner(url: str, model: str, messages: List[Dict], temperat
             yield f'event: error\ndata: {json.dumps({"error": "Network error", "status": 502, "fallback_eligible": False})}\n\n'
         except Exception as e:
             logger.error(f"Ollama stream error: {e}")
-            yield f'event: error\ndata: {json.dumps({"error": str(e), "status": 502, "fallback_eligible": False})}\n\n'
+            yield f'event: error\ndata: {json.dumps({"error": _stream_failure_message(e), "status": 502, "fallback_eligible": False})}\n\n'
         return
 
     # ── Anthropic streaming ──
@@ -3402,7 +3402,7 @@ async def _stream_llm_inner(url: str, model: str, messages: List[Dict], temperat
             yield f'event: error\ndata: {json.dumps({"error": "Network error", "status": 502, "fallback_eligible": False})}\n\n'
         except Exception as e:
             logger.error(f"Anthropic stream error: {e}")
-            yield f'event: error\ndata: {json.dumps({"error": str(e), "status": 502, "fallback_eligible": False})}\n\n'
+            yield f'event: error\ndata: {json.dumps({"error": _stream_failure_message(e), "status": 502, "fallback_eligible": False})}\n\n'
         return
 
     # ── OpenAI-compatible streaming ──
@@ -3872,7 +3872,17 @@ async def _stream_llm_inner(url: str, model: str, messages: List[Dict], temperat
         yield f'event: error\ndata: {json.dumps({"error": "Network error", "status": 502, "fallback_eligible": False})}\n\n'
     except Exception as e:
         logger.error(f"Stream error: {e}")
-        yield f'event: error\ndata: {json.dumps({"error": str(e), "status": 502, "fallback_eligible": False})}\n\n'
+        yield f'event: error\ndata: {json.dumps({"error": _stream_failure_message(e), "status": 502, "fallback_eligible": False})}\n\n'
+
+
+def _stream_failure_message(error: BaseException) -> str:
+    """Client-facing text for an unexpected streaming failure.
+
+    The raw exception can carry request URLs, local paths or provider internals;
+    callers log it server-side and stream only this generic message, like the
+    named transport failures above it.
+    """
+    return f"Model stream failed ({type(error).__name__})"
 
 
 def _summarize_stream_error(err_chunk: Optional[str]) -> str:
diff --git a/src/mail_attachment_paths.py b/src/mail_attachment_paths.py
new file mode 100644
index 000000000..a2eb9c912
--- /dev/null
+++ b/src/mail_attachment_paths.py
@@ -0,0 +1,32 @@
+"""Per-principal extraction directories for email attachments.
+
+Shared by the HTTP email routes and the email MCP server, which both extract
+attachments under MAIL_ATTACHMENTS_DIR.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import json
+from pathlib import Path
+
+
+def attachment_scope_dir(root, folder, uid, *, owner, account_id) -> Path:
+    """Return the extraction directory for one message's attachments.
+
+    IMAP UIDs are small per-mailbox counters and folder names are server- or
+    caller-supplied (`/`-delimited hierarchies, absolute or `..` segments), so
+    neither may become a path. The directory is one hex segment derived from
+    (owner, account, folder, uid): distinct principals and mailboxes never
+    share it, and no input can steer it out of *root*. Containment is checked
+    after resolution, so a symlinked entry cannot redirect it either.
+    """
+    scope = json.dumps(
+        [str(owner or ""), str(account_id or ""), str(folder or ""), str(uid or "")],
+        ensure_ascii=False,
+    )
+    base = Path(root).resolve()
+    target = (base / hashlib.sha256(scope.encode("utf-8")).hexdigest()[:32]).resolve()
+    if target.parent != base:
+        raise ValueError("attachment directory escapes the extraction root")
+    return target
diff --git a/src/readiness.py b/src/readiness.py
index 6d6060c3b..03f4e847d 100644
--- a/src/readiness.py
+++ b/src/readiness.py
@@ -6,11 +6,14 @@ writable, and storage is local-first. Served by ``GET /api/ready`` and suitable
 for an orchestrator readiness probe (200 only when every critical check passes).
 """
 
+import logging
 import os
 import uuid
 from datetime import datetime
 from typing import Dict
 
+logger = logging.getLogger(__name__)
+
 
 def check_readiness() -> Dict[str, object]:
     """Run the readiness checks and return a JSON-serialisable report.
@@ -33,7 +36,10 @@ def check_readiness() -> Dict[str, object]:
             conn.execute(sql_text("SELECT 1"))
         checks["database"] = {"ok": True}
     except Exception as e:
-        checks["database"] = {"ok": False, "error": str(e)}
+        # The raw driver error can carry the DB host/user/path; keep it in the
+        # server log and give the client only the exception type.
+        logger.warning("Readiness database check failed: %s", e)
+        checks["database"] = {"ok": False, "error_type": type(e).__name__}
 
     # Data directory present and writable — home must be able to hold its own data.
     try:
@@ -44,7 +50,8 @@ def check_readiness() -> Dict[str, object]:
         os.remove(probe)
         checks["data_dir"] = {"ok": True, "path": DATA_DIR}
     except Exception as e:
-        checks["data_dir"] = {"ok": False, "error": str(e)}
+        logger.warning("Readiness data_dir check failed: %s", e)
+        checks["data_dir"] = {"ok": False, "error_type": type(e).__name__}
 
     # Local-first: storage stays on the home machine (informational, never fatal).
     local_first = (
diff --git a/src/text_helpers.py b/src/text_helpers.py
index 80207ee89..31a83bff3 100644
--- a/src/text_helpers.py
+++ b/src/text_helpers.py
@@ -193,3 +193,17 @@ def strip_think(text: str, *, prose: bool = False, prompt_echo: bool = True) ->
 # from `src.research_utils` working while delegating to the central impl.
 def strip_thinking(text: str) -> str:
     return strip_think(text or "", prose=False, prompt_echo=True)
+
+
+_CLOSED_THINK_OPEN_RE = re.compile(r"<think(?:ing)?>", re.IGNORECASE)
+_CLOSED_THINK_CLOSE_RE = re.compile(r"</think(?:ing)?>", re.IGNORECASE)
+
+
+def strip_closed_think_blocks(text: str) -> str:
+    """Remove closed ``<think>``/``<thinking>`` blocks, leaving everything else.
+
+    Same result as ``re.sub(r'<think(?:ing)?>[\\s\\S]*?</think(?:ing)?>', '', text,
+    flags=re.I)`` but forward-only (see _sub_delimited), so an unclosed opener
+    flood in model output stays O(n) instead of O(n^2).
+    """
+    return _sub_delimited(text or "", _CLOSED_THINK_OPEN_RE, _CLOSED_THINK_CLOSE_RE, lambda _inner: "")
diff --git a/src/tools/calendar.py b/src/tools/calendar.py
index 611b3e59b..3eeacda72 100644
--- a/src/tools/calendar.py
+++ b/src/tools/calendar.py
@@ -236,10 +236,10 @@ async def do_manage_calendar(content: str, owner: Optional[str] = None, *, impor
         text = str(raw).strip().lower()
         if text in {"none", "no", "off", "false"}:
             return None
-        m = re.search(r"(\d+)\s*(?:minutes?|mins?|m)\b", text)
+        m = re.search(r"(?<!\d)(\d+)\s*(?:minutes?|mins?|m)\b", text)
         if m:
             return max(0, int(m.group(1)))
-        m = re.search(r"(\d+)\s*(?:hours?|hrs?|h)\b", text)
+        m = re.search(r"(?<!\d)(\d+)\s*(?:hours?|hrs?|h)\b", text)
         if m:
             return max(0, int(m.group(1)) * 60)
         if text.isdigit():
@@ -251,7 +251,7 @@ async def do_manage_calendar(content: str, owner: Optional[str] = None, *, impor
         if minutes_before is None:
             return desc
         reminder_only = re.compile(
-            r"^\s*(?:remind(?:er)?|alarm)\s*:?\s*\d+\s*"
+            r"^\s*(?:remind(?:er)?|alarm)\s*(?::\s*)?\d+\s*"
             r"(?:minutes?|mins?|m|hours?|hrs?|h)\b.*$",
             re.I,
         )
@@ -497,8 +497,8 @@ async def do_manage_calendar(content: str, owner: Optional[str] = None, *, impor
                 delta = None
                 if dur:
                     import re as _re_d
-                    h = _re_d.search(r'(\d+)\s*(?:h|hr|hours?)', dur)
-                    m = _re_d.search(r'(\d+)\s*(?:m|min|minutes?)', dur)
+                    h = _re_d.search(r'(?<!\d)(\d+)\s*(?:h|hr|hours?)', dur)
+                    m = _re_d.search(r'(?<!\d)(\d+)\s*(?:m|min|minutes?)', dur)
                     secs = (int(h.group(1)) * 3600 if h else 0) + (int(m.group(1)) * 60 if m else 0)
                     if secs > 0:
                         delta = timedelta(seconds=secs)
diff --git a/src/tools/notes.py b/src/tools/notes.py
index f464e0dca..a28cda78c 100644
--- a/src/tools/notes.py
+++ b/src/tools/notes.py
@@ -322,7 +322,7 @@ async def do_manage_notes(content: str, owner: Optional[str] = None) -> Dict:
                 if looks_like_reminder:
                     temporal = re.search(
                         r"\b(?:today|tonight|tomorrow|tmrw|yesterday)\b(?:\s+(?:at\s+)?\d{1,2}(?::\d{2})?\s*(?:am|pm)?)?"
-                        r"|\b\d{1,2}(?::\d{2})?\s*(?:am|pm)?\s+(?:today|tonight|tomorrow|tmrw|yesterday)\b"
+                        r"|\b\d{1,2}(?::\d{2})?(?:\s*(?:am|pm))?\s+(?:today|tonight|tomorrow|tmrw|yesterday)\b"
                         r"|\bin\s+\d+\s*(?:hour|hr|minute|min|day)s?\b",
                         lower_combined,
                     )
diff --git a/src/upload_handler.py b/src/upload_handler.py
index ce87120d0..0d0a14065 100644
--- a/src/upload_handler.py
+++ b/src/upload_handler.py
@@ -63,19 +63,80 @@ INTERNAL_UPLOAD_URL_RE = re.compile(
     r"([0-9a-fA-F]{32}(?:\.[A-Za-z0-9]+)?)"
     r"(?=$|[\s\"'<>\[\](){},;!?:&#]|\.(?![A-Za-z0-9]))"
 )
-PDF_SOURCE_UPLOAD_RE = re.compile(
-    r"<!--\s*pdf(?:_form)?_source\b[^>]*\bupload_id="
-    r"[\"']([0-9a-fA-F]{32}(?:\.[A-Za-z0-9]+)?)[\"'][^>]*-->",
+# `<!--\s*pdf(?:_form)?_source\b[^>]*\bupload_id=["'](id)["'][^>]*-->` and
+# `\[Attachment:[^\]\r\n]*\|\s*id=(id)(?:\s*\||\s*\])` are matched by the
+# forward-only scanners below. As single regexes, every opener in a run with no
+# closing `>` / `]` rescanned to the end of that run: O(n^2) on chat content,
+# which is unbounded on persisted assistant output (CodeQL py/polynomial-redos).
+_PDF_SOURCE_OPEN_RE = re.compile(r"<!--\s*pdf(?:_form)?_source\b", re.IGNORECASE)
+_PDF_SOURCE_ID_RE = re.compile(
+    r"\bupload_id=[\"']([0-9a-fA-F]{32}(?:\.[A-Za-z0-9]+)?)[\"']",
     re.IGNORECASE,
 )
-ATTACHMENT_REFERENCE_LINE_RE = re.compile(
-    r"\[Attachment:[^\]\r\n]*\|\s*id="
-    r"([0-9a-fA-F]{32}(?:\.[A-Za-z0-9]+)?)"
-    r"(?:\s*\||\s*\])",
+_ATTACHMENT_REFERENCE_OPEN_RE = re.compile(r"\[Attachment:", re.IGNORECASE)
+_ATTACHMENT_REFERENCE_STOP_RE = re.compile(r"[\]\r\n]")
+_ATTACHMENT_REFERENCE_TAIL_RE = re.compile(
+    r"\|\s*id=([0-9a-fA-F]{32}(?:\.[A-Za-z0-9]+)?)(?:\s*\||\s*\])",
     re.IGNORECASE,
 )
 
 
+def _pdf_source_upload_ids(value: str) -> list[str]:
+    """IDs from `<!-- pdf_source ... upload_id="<id>" ... -->` comments.
+
+    Every opener before the next `>` shares that `>`: the comment matches only
+    if `--` sits right before it, and then with the last `upload_id=` (the
+    greedy `[^>]*` backtracks from the right). Otherwise all of those openers
+    fail together, so the scan resumes after the `>`.
+    """
+    found: list[str] = []
+    pos = 0
+    while True:
+        opener = _PDF_SOURCE_OPEN_RE.search(value, pos)
+        if opener is None:
+            return found
+        close = value.find(">", opener.end())
+        if close < 0:
+            return found
+        if value[close - 2:close] == "--":
+            last = None
+            for last in _PDF_SOURCE_ID_RE.finditer(value, opener.end(), close):
+                pass
+            if last is not None:
+                found.append(last.group(1))
+        pos = close + 1
+
+
+def _attachment_reference_ids(value: str) -> list[str]:
+    """IDs from `[Attachment: name | id=<id> | ...]` reference lines.
+
+    The label scan stops at the first `]`/CR/LF, so every opener before that
+    stop shares it and can only use the last `|` (scanning right to left)
+    whose tail matches. If none does, all of those openers fail together and
+    the scan resumes at the stop.
+    """
+    found: list[str] = []
+    pos = 0
+    while True:
+        opener = _ATTACHMENT_REFERENCE_OPEN_RE.search(value, pos)
+        if opener is None:
+            return found
+        stop = _ATTACHMENT_REFERENCE_STOP_RE.search(value, opener.end())
+        end = stop.start() if stop else len(value)
+        tail = None
+        pipe = value.rfind("|", opener.end(), end)
+        while pipe >= 0:
+            tail = _ATTACHMENT_REFERENCE_TAIL_RE.match(value, pipe)
+            if tail is not None:
+                break
+            pipe = value.rfind("|", opener.end(), pipe)
+        if tail is None:
+            pos = end
+        else:
+            found.append(tail.group(1))
+            pos = tail.end()
+
+
 def is_valid_upload_id(upload_id: str) -> bool:
     """Return True when *upload_id* matches the canonical uploads.json id format."""
     return UPLOAD_ID_RE.fullmatch(upload_id or "") is not None
@@ -110,8 +171,8 @@ def extract_internal_upload_ids(value: Any) -> set[str]:
         return set()
     return (
         set(INTERNAL_UPLOAD_URL_RE.findall(value))
-        | set(PDF_SOURCE_UPLOAD_RE.findall(value))
-        | set(ATTACHMENT_REFERENCE_LINE_RE.findall(value))
+        | set(_pdf_source_upload_ids(value))
+        | set(_attachment_reference_ids(value))
     )
 
 
diff --git a/src/url_safety.py b/src/url_safety.py
index e0f66cfeb..4203a7d1d 100644
--- a/src/url_safety.py
+++ b/src/url_safety.py
@@ -154,3 +154,52 @@ def check_outbound_url(
     if not saw_ip:
         return False, "host does not resolve to an IP"
     return True, "ok"
+
+
+
+class OutboundAddressBlocked(PermissionError):
+    """A non-HTTP outbound host resolves into a disallowed address range."""
+
+
+def connect_outbound_tcp(
+    host: str,
+    port: int,
+    *,
+    timeout=socket._GLOBAL_DEFAULT_TIMEOUT,
+    block_private: bool = False,
+    source_address=None,
+    resolver: Optional[Callable[..., list]] = None,
+) -> socket.socket:
+    """Open a TCP connection to *host* under the outbound address policy.
+
+    For raw TCP clients (IMAP/SMTP). The host is resolved exactly once, every
+    resolved address is judged with the same policy as check_outbound_url, and
+    the socket connects only to those already-judged addresses. A second
+    lookup at connect time (what socket.create_connection(host) does) would let
+    a rebinding name pass the check with a public answer and then connect to
+    metadata/private space. TLS callers keep wrapping the returned socket with
+    ``server_hostname=host``, so SNI and certificate checks are unchanged.
+    """
+    resolve = resolver or socket.getaddrinfo
+    infos = resolve(host, port, 0, socket.SOCK_STREAM)
+    for _family, _type, _proto, _canon, sockaddr in infos:
+        ip = ipaddress.ip_address(str(sockaddr[0]).split("%")[0])
+        reason = _classify(ip, block_private=block_private)
+        if reason:
+            raise OutboundAddressBlocked(reason)
+    last_error: Optional[OSError] = None
+    for family, socktype, proto, _canon, sockaddr in infos:
+        sock = socket.socket(family, socktype, proto)
+        try:
+            if timeout is not socket._GLOBAL_DEFAULT_TIMEOUT:  # same contract as create_connection
+                sock.settimeout(timeout)
+            if source_address:
+                sock.bind(source_address)
+            sock.connect(sockaddr)
+            return sock
+        except OSError as exc:
+            last_error = exc
+            sock.close()
+    if last_error is not None:
+        raise last_error
+    raise socket.gaierror(socket.EAI_NONAME, f"{host} did not resolve to an address")
diff --git a/tests/test_calendar_reminder_minutes_parsing.py b/tests/test_calendar_reminder_minutes_parsing.py
index 6762fe33d..64f898d5b 100644
--- a/tests/test_calendar_reminder_minutes_parsing.py
+++ b/tests/test_calendar_reminder_minutes_parsing.py
@@ -123,3 +123,37 @@ async def test_update_event_can_add_reminder_after_creation():
         assert note is not None, "update_event should create the reminder note"
     finally:
         db.close()
+
+
+async def test_reminder_and_duration_parsers_stay_linear_on_digit_and_space_floods():
+    """CodeQL py/polynomial-redos: `(\\d+)\\s*unit` rescanned a digit run from
+    every offset and `alarm\\s*:?\\s*\\d+` split one whitespace run two ways.
+    Tool arguments come from model output, so keep them O(n)."""
+    import time
+    from src.tool_implementations import do_manage_calendar
+
+    owner = "tester-" + uuid.uuid4().hex[:6]
+    started = time.perf_counter()
+    res = await do_manage_calendar(json.dumps({
+        "action": "create_event",
+        "summary": "Flood",
+        "dtstart": "2030-04-01T10:00:00",
+        "reminder_minutes": "0" * 40_000 + "x",
+        "duration": "0" * 40_000 + "x",
+    }), owner=owner)
+    assert time.perf_counter() - started < 2.0
+    assert res.get("exit_code") == 0, res
+    assert "reminder set" not in res.get("response", ""), res
+
+    # A reminder is set, so the "is the description only a reminder?" check runs.
+    started = time.perf_counter()
+    res = await do_manage_calendar(json.dumps({
+        "action": "create_event",
+        "summary": "Flood 2",
+        "dtstart": "2030-04-02T10:00:00",
+        "description": "alarm" + "\t" * 40_000,
+        "reminder_minutes": 5,
+    }), owner=owner)
+    assert time.perf_counter() - started < 2.0
+    assert res.get("exit_code") == 0, res
+    assert "reminder 5 min before" in res.get("response", ""), res
diff --git a/tests/test_codeql_python_residual_closure.py b/tests/test_codeql_python_residual_closure.py
new file mode 100644
index 000000000..cfcfdb5d0
--- /dev/null
+++ b/tests/test_codeql_python_residual_closure.py
@@ -0,0 +1,522 @@
+"""Final closure tests for the residual Python CodeQL lane (PR #6503).
+
+1. MCP attachment extraction: no traversal, per owner/account directories.
+2. Mail DNS rebinding: one resolution, connect only to the checked address,
+   TLS SNI/verification still against the requested hostname.
+3. /accounts/test runs its blocking mail I/O off the event loop.
+4. /search/web works under the production CSP and payloads cannot execute.
+5. Outbound mail address policy matrix.
+"""
+
+import asyncio
+import json
+import os
+import re
+import shutil
+import socket
+import subprocess
+import threading
+import time
+import urllib.parse
+from email.mime.application import MIMEApplication
+from email.mime.multipart import MIMEMultipart
+from pathlib import Path
+from types import SimpleNamespace
+
+import pytest
+
+
+# -- 1. MCP attachment extraction -------------------------------------------
+
+def _message_with_attachment(body: bytes) -> bytes:
+    msg = MIMEMultipart()
+    part = MIMEApplication(body, Name="invoice.pdf")
+    part["Content-Disposition"] = 'attachment; filename="invoice.pdf"'
+    msg.attach(part)
+    return msg.as_bytes()
+
+
+@pytest.fixture
+def mcp_mail(tmp_path, monkeypatch):
+    import mcp_servers.email_server as es
+
+    root = tmp_path / "mail-attachments"
+    root.mkdir()
+    monkeypatch.setattr(es, "MAIL_ATTACHMENTS_DIR", str(root))
+    monkeypatch.setattr(es, "_fixture_attachment_source", lambda *a, **k: None)
+    monkeypatch.setattr(es, "_load_config", lambda account=None: {"account_id": account})
+    box = {"raw": _message_with_attachment(b"%PDF one")}
+
+    class _Conn:
+        def select(self, *a, **k):
+            return ("OK", [b"1"])
+
+        def uid(self, *a):
+            return ("OK", [(b"42 (BODY[])", box["raw"])])
+
+        def logout(self):
+            pass
+
+    monkeypatch.setattr(es, "_imap_connect", lambda account=None: _Conn())
+    return es, root.resolve(), box
+
+
+@pytest.mark.parametrize("folder,uid", [
+    ("/tmp/odysseus-escape", "42"),          # absolute mailbox name replaced the root
+    ("../../escape", "42"),                  # relative traversal
+    ("INBOX/../../../escape", "42"),          # hierarchy delimiter + traversal
+    ("..", ".."),
+    ("INBOX", "../../42"),
+    ("INBOX/Receipts", "42"),                 # legitimate hierarchical folder
+])
+def test_mcp_download_attachment_stays_in_one_root_segment(mcp_mail, folder, uid):
+    es, root, _box = mcp_mail
+    result = es._download_attachment(uid, 0, folder)
+    path = Path(result["path"]).resolve()
+    assert path.parent.parent == root, path
+    assert path.read_bytes() == b"%PDF one"
+
+
+def test_mcp_download_attachment_isolates_owners_and_accounts(mcp_mail):
+    es, _root, box = mcp_mail
+    paths = {}
+    for owner, account, body in (
+        ("alice", "acct-a", b"%PDF alice"),
+        ("bob", "acct-a", b"%PDF bob"),
+        ("alice", "acct-b", b"%PDF alice second mailbox"),
+    ):
+        token = es._CURRENT_OWNER.set(owner)
+        try:
+            box["raw"] = _message_with_attachment(body)
+            paths[(owner, account)] = (es._download_attachment("42", 0, "INBOX", account=account)["path"], body)
+        finally:
+            es._CURRENT_OWNER.reset(token)
+    assert len({p for p, _ in paths.values()}) == 3
+    for path, body in paths.values():
+        assert Path(path).read_bytes() == body
+
+
+def test_attachment_scope_dir_rejects_symlinked_scope(tmp_path):
+    from src.mail_attachment_paths import attachment_scope_dir
+
+    root = tmp_path / "root"
+    root.mkdir()
+    target = attachment_scope_dir(root, "INBOX", "1", owner="o", account_id="a")
+    outside = tmp_path / "outside"
+    outside.mkdir()
+    target.symlink_to(outside, target_is_directory=True)
+    with pytest.raises(ValueError):
+        attachment_scope_dir(root, "INBOX", "1", owner="o", account_id="a")
+
+
+def test_attachment_scope_dir_normalises_uid_type(tmp_path):
+    from src.mail_attachment_paths import attachment_scope_dir
+
+    assert attachment_scope_dir(tmp_path, "INBOX", 42, owner="o", account_id=None) == \
+        attachment_scope_dir(tmp_path, "INBOX", "42", owner="o", account_id="")
+
+
+# -- 2. DNS rebinding: resolve once, connect to the checked address ------------
+
+class _LineServer:
+    """Tiny loopback server speaking just enough IMAP or SMTP for a handshake."""
+
+    def __init__(self, protocol):
+        self.protocol = protocol
+        self.sock = socket.socket()
+        self.sock.bind(("127.0.0.1", 0))
+        self.sock.listen(4)
+        self.port = self.sock.getsockname()[1]
+        self.thread = threading.Thread(target=self._serve, daemon=True)
+        self.thread.start()
+
+    def _serve(self):
+        try:
+            conn, _ = self.sock.accept()
+        except OSError:
+            return
+        with conn, conn.makefile("rwb") as io:
+            io.write(b"* OK ready\r\n" if self.protocol == "imap" else b"220 fake ESMTP\r\n")
+            io.flush()
+            for raw in io:
+                line = raw.decode().strip()
+                if self.protocol == "imap":
+                    tag, _, command = line.partition(" ")
+                    if command.upper().startswith("CAPABILITY"):
+                        io.write(f"* CAPABILITY IMAP4rev1\r\n{tag} OK done\r\n".encode())
+                    else:
+                        io.write(f"* BYE\r\n{tag} OK bye\r\n".encode())
+                        io.flush()
+                        return
+                elif line.upper().startswith(("EHLO", "HELO")):
+                    io.write(b"250 fake\r\n")
+                else:
+                    io.write(b"221 bye\r\n")
+                    io.flush()
+                    return
+                io.flush()
+
+    def close(self):
+        self.sock.close()
+
+
+@pytest.fixture
+def rebinding_dns(monkeypatch):
+    """`rebind.test` answers loopback once, then the metadata address."""
+    real = socket.getaddrinfo
+    lookups = []
+
+    def _resolve(host, port, *args, **kwargs):
+        if host == "rebind.test":
+            lookups.append(host)
+            ip = "127.0.0.1" if len(lookups) == 1 else "169.254.169.254"
+            return [(socket.AF_INET, socket.SOCK_STREAM, 6, "", (ip, port))]
+        return real(host, port, *args, **kwargs)
+
+    monkeypatch.setattr(socket, "getaddrinfo", _resolve)
+    return lookups
+
+
+class _RecordingTLS:
+    """Stands in for an SSLContext: records the SNI name, keeps the socket plain."""
+
+    def __init__(self):
+        self.server_hostname = None
+
+    def wrap_socket(self, sock, server_hostname=None, **_kwargs):
+        self.server_hostname = server_hostname
+        return sock
+
+
+@pytest.mark.parametrize("tls", [False, True])
+def test_imap_connects_to_the_checked_address_only(rebinding_dns, tls):
+    from routes.email.email_helpers import _PolicyIMAP4, _PolicyIMAP4_SSL
+
+    server = _LineServer("imap")
+    try:
+        if tls:
+            context = _RecordingTLS()
+            conn = _PolicyIMAP4_SSL("rebind.test", server.port, block_private=False, timeout=5, ssl_context=context)
+            assert context.server_hostname == "rebind.test"
+        else:
+            conn = _PolicyIMAP4("rebind.test", server.port, block_private=False, timeout=5)
+        assert conn.sock.getpeername()[0] == "127.0.0.1"
+        conn.logout()
+    finally:
+        server.close()
+    assert rebinding_dns == ["rebind.test"]  # a second lookup would have answered 169.254.169.254
+
+
+@pytest.mark.parametrize("tls", [False, True])
+def test_smtp_connects_to_the_checked_address_only(rebinding_dns, tls):
+    from routes.email.email_helpers import _PolicySMTP, _PolicySMTP_SSL
+
+    server = _LineServer("smtp")
+    try:
+        if tls:
+            context = _RecordingTLS()
+            smtp = _PolicySMTP_SSL("rebind.test", server.port, block_private=False, timeout=5, context=context)
+            assert context.server_hostname == "rebind.test"
+        else:
+            smtp = _PolicySMTP("rebind.test", server.port, block_private=False, timeout=5)
+        assert smtp.sock.getpeername()[0] == "127.0.0.1"
+        assert smtp.ehlo()[0] == 250
+        smtp.quit()
+    finally:
+        server.close()
+    assert rebinding_dns == ["rebind.test"]
+
+
+def test_any_denied_answer_in_a_mixed_resolution_blocks_the_connection():
+    from src.url_safety import OutboundAddressBlocked, connect_outbound_tcp
+
+    def _mixed(host, port, *args):
+        return [
+            (socket.AF_INET, socket.SOCK_STREAM, 6, "", ("93.184.216.34", port)),
+            (socket.AF_INET, socket.SOCK_STREAM, 6, "", ("169.254.169.254", port)),
+        ]
+
+    with pytest.raises(OutboundAddressBlocked):
+        connect_outbound_tcp("mixed.test", 993, block_private=False, resolver=_mixed)
+
+
+# -- 5. Address/principal policy matrix ----------------------------------------
+
+_ALWAYS_DENIED = [
+    "169.254.169.254", "fe80::1", "0.0.0.0", "::", "224.0.0.1", "240.0.0.1",
+    "::ffff:169.254.169.254", "64:ff9b::a9fe:a9fe", "64:ff9b::a00:5",
+    "::1",  # IPv6 loopback sits in ::/8, which the existing policy treats as reserved
+]
+_PRIVATE = ["127.0.0.1", "10.0.0.5", "172.16.0.1", "192.168.1.10", "100.64.0.1", "fd00::1"]
+_PUBLIC = ["93.184.216.34", "2606:2800:220:1::1"]
+
+
+@pytest.fixture
+def fake_sockets(monkeypatch):
+    import src.url_safety as url_safety
+
+    connected = []
+
+    class _Sock:
+        def __init__(self, *args):
+            pass
+
+        def settimeout(self, timeout):
+            pass
+
+        def bind(self, address):
+            pass
+
+        def connect(self, sockaddr):
+            connected.append(sockaddr[0])
+
+        def close(self):
+            pass
+
+    monkeypatch.setattr(url_safety.socket, "socket", _Sock)
+    return connected
+
+
+def _answer(ip):
+    family = socket.AF_INET6 if ":" in ip else socket.AF_INET
+    return lambda host, port, *args: [(family, socket.SOCK_STREAM, 6, "", (ip, port))]
+
+
+@pytest.mark.parametrize("block_private", [False, True])
+@pytest.mark.parametrize("ip", _ALWAYS_DENIED)
+def test_metadata_and_special_ranges_are_always_denied(fake_sockets, ip, block_private):
+    from src.url_safety import OutboundAddressBlocked, connect_outbound_tcp
+
+    with pytest.raises(OutboundAddressBlocked):
+        connect_outbound_tcp("h", 993, block_private=block_private, resolver=_answer(ip))
+    assert fake_sockets == []
+
+
+@pytest.mark.parametrize("ip", _PRIVATE)
+def test_private_ranges_follow_the_principal_policy(fake_sockets, ip):
+    from src.url_safety import OutboundAddressBlocked, connect_outbound_tcp
+
+    connect_outbound_tcp("h", 993, block_private=False, resolver=_answer(ip))
+    assert fake_sockets == [ip]
+    with pytest.raises(OutboundAddressBlocked):
+        connect_outbound_tcp("h", 993, block_private=True, resolver=_answer(ip))
+
+
+@pytest.mark.parametrize("ip", _PUBLIC)
+def test_public_mail_servers_are_always_allowed(fake_sockets, ip):
+    from src.url_safety import connect_outbound_tcp
+
+    connect_outbound_tcp("h", 993, block_private=True, resolver=_answer(ip))
+    assert fake_sockets == [ip]
+
+
+@pytest.mark.parametrize("trusted,env,owner,blocked", [
+    (False, {}, "bob", True),                                   # multi-user, non-admin: denied
+    (False, {}, "", True),                                      # multi-user, no principal: denied
+    (True, {}, "admin", False),                                 # admin (or single-user mode)
+    (False, {"EMAIL_ALLOW_PRIVATE_IPS": "true"}, "bob", False),  # operator opt-in for LAN mail
+    (True, {"EMAIL_BLOCK_PRIVATE_IPS": "true"}, "admin", True),  # operator lockdown wins
+    (False, {"EMAIL_ALLOW_PRIVATE_IPS": "true", "EMAIL_BLOCK_PRIVATE_IPS": "true"}, "bob", True),
+])
+def test_private_mail_destination_principal_matrix(monkeypatch, trusted, env, owner, blocked):
+    import src.tool_security as tool_security
+    from routes.email.email_helpers import _mail_private_blocked
+
+    for key in ("EMAIL_ALLOW_PRIVATE_IPS", "EMAIL_BLOCK_PRIVATE_IPS"):
+        monkeypatch.delenv(key, raising=False)
+    for key, value in env.items():
+        monkeypatch.setenv(key, value)
+    monkeypatch.setattr(tool_security, "owner_is_admin_or_single_user", lambda o: trusted)
+    assert _mail_private_blocked(owner) is blocked
+
+
+def test_single_user_mode_allows_lan_mail_servers(monkeypatch):
+    from routes.email.email_helpers import _mail_private_blocked
+
+    for key in ("EMAIL_ALLOW_PRIVATE_IPS", "EMAIL_BLOCK_PRIVATE_IPS"):
+        monkeypatch.delenv(key, raising=False)
+    monkeypatch.setenv("AUTH_ENABLED", "false")
+    assert _mail_private_blocked("") is False
+
+
+def test_non_admin_cannot_probe_loopback_through_the_connection_test(monkeypatch):
+    import routes.email_routes as email_routes
+    import src.tool_security as tool_security
+
+    for key in ("EMAIL_ALLOW_PRIVATE_IPS", "EMAIL_BLOCK_PRIVATE_IPS"):
+        monkeypatch.delenv(key, raising=False)
+    monkeypatch.setattr(tool_security, "owner_is_admin_or_single_user", lambda o: False)
+    endpoint = _accounts_test_endpoint(email_routes)
+
+    class _Request:
+        async def json(self):
+            return {"imap_host": "127.0.0.1", "imap_port": 6379, "imap_user": "u", "imap_password": "p",
+                    "smtp_host": "10.0.0.5", "smtp_port": 25}
+
+    result = asyncio.run(endpoint(req=_Request(), owner="bob"))
+    assert result["imap"]["error"] == "IMAP server address is not allowed by this server's network policy"
+    assert result["smtp"]["error"] == "SMTP server address is not allowed by this server's network policy"
+
+
+# -- 3. /accounts/test blocking I/O stays off the event loop -----------------------
+
+def _accounts_test_endpoint(email_routes):
+    router = email_routes.setup_email_routes()
+    return next(
+        r.endpoint for r in router.routes
+        if r.path == "/api/email/accounts/test" and "POST" in getattr(r, "methods", set())
+    )
+
+
+def test_connection_test_does_not_block_the_event_loop(monkeypatch):
+    import routes.email_routes as email_routes
+
+    def _slow_open(host, port, **kwargs):
+        time.sleep(1.0)  # a mail server that never answers within the timeout
+        raise socket.timeout("timed out")
+
+    monkeypatch.setattr(email_routes, "_open_imap_connection", _slow_open)
+    endpoint = _accounts_test_endpoint(email_routes)
+
+    class _Request:
+        async def json(self):
+            return {"imap_host": "imap.example.com", "imap_port": 993, "imap_user": "u", "imap_password": "p"}
+
+    async def _main():
+        gaps = []
+        done = asyncio.Event()
+
+        async def _heartbeat():
+            last = time.perf_counter()
+            while not done.is_set():
+                await asyncio.sleep(0.02)
+                now = time.perf_counter()
+                gaps.append(now - last)
+                last = now
+
+        beat = asyncio.create_task(_heartbeat())
+        started = time.perf_counter()
+        results = await asyncio.gather(*(endpoint(req=_Request(), owner="alice") for _ in range(3)))
+        elapsed = time.perf_counter() - started
+        done.set()
+        await beat
+        return results, max(gaps), elapsed
+
+    results, worst_gap, elapsed = asyncio.run(_main())
+    assert worst_gap < 0.5, f"event loop stalled for {worst_gap:.2f}s"
+    assert elapsed < 2.5  # three 1s probes overlapped instead of serialising on the loop
+    for result in results:
+        assert result == {"ok": False, "imap": {"ok": False, "error": "IMAP connection timed out"}, "smtp": None}
+
+
+def test_connection_test_keeps_its_authentication_dependency():
+    import routes.email_routes as email_routes
+    from routes.email.email_routes import require_user
+
+    router = email_routes.setup_email_routes()
+    route = next(
+        r for r in router.routes
+        if r.path == "/api/email/accounts/test" and "POST" in getattr(r, "methods", set())
+    )
+    assert any(dep.call is require_user for dep in route.dependant.dependencies)
+
+
+# -- 4. /search/web under the production CSP ---------------------------------------
+
+_PAYLOAD = (
+    "</script><script>document.title='PWNED'</script>"
+    "<img src=x onerror=\"document.body.dataset.pwned='1'\">"
+)
+_SOURCES = [
+    {"title": "Example result", "url": "https://example.com/a", "snippet": "first"},
+    {"title": "Script link", "url": "javascript:document.body.dataset.pwned='2'", "snippet": "second"},
+]
+
+
+def _csp_app():
+    from fastapi import FastAPI
+    from fastapi.responses import HTMLResponse
+    from core.middleware import SecurityHeadersMiddleware
+    from routes.search.search_routes import setup_search_routes
+
+    app = FastAPI()
+    app.add_middleware(SecurityHeadersMiddleware)
+
+    @app.post("/api/search")
+    async def _stub_search():
+        return {"sources": _SOURCES}
+
+    @app.get("/csp-control")
+    async def _control():
+        return HTMLResponse("<html><body><script>document.body.dataset.ran='1'</script></body></html>")
+
+    app.include_router(setup_search_routes(SimpleNamespace()))
+    return app
+
+
+@pytest.mark.parametrize("q", ["weather in lisbon", _PAYLOAD])
+def test_search_page_script_carries_the_response_csp_nonce(q):
+    from fastapi.testclient import TestClient
+
+    response = TestClient(_csp_app()).get("/search/web", params={"q": q})
+    csp = response.headers["content-security-policy"]
+    nonce = re.search(r"'nonce-([^']+)'", csp).group(1)
+    assert "unsafe-inline" not in csp.split("script-src", 1)[1].split(";", 1)[0]
+    scripts = re.findall(r"<script\b[^>]*>", response.text, re.I)
+    assert scripts == [f'<script nonce="{nonce}">']
+    markup = response.text.split("<script", 1)[0]
+    assert "<img" not in markup.lower()  # the payload is only ever present HTML-escaped
+
+
+def _chrome():
+    for name in ("google-chrome", "google-chrome-stable", "chromium", "chromium-browser"):
+        path = shutil.which(name)
+        if path:
+            return path
+    return None
+
+
+@pytest.fixture
+def live_csp_server():
+    uvicorn = pytest.importorskip("uvicorn")
+    with socket.socket() as probe:
+        probe.bind(("127.0.0.1", 0))
+        port = probe.getsockname()[1]
+    server = uvicorn.Server(uvicorn.Config(_csp_app(), host="127.0.0.1", port=port, log_level="error"))
+    thread = threading.Thread(target=server.run, daemon=True)
+    thread.start()
+    deadline = time.time() + 10
+    while not server.started and time.time() < deadline:
+        time.sleep(0.05)
+    yield f"http://127.0.0.1:{port}"
+    server.should_exit = True
+    thread.join(timeout=10)
+
+
+def _render(chrome, url, profile):
+    out = subprocess.run(
+        [chrome, "--headless=new", "--disable-gpu", "--no-sandbox", "--no-first-run",
+         f"--user-data-dir={profile}", "--virtual-time-budget=5000", "--dump-dom", url],
+        capture_output=True, text=True, timeout=90,
+    )
+    return out.stdout
+
+
+@pytest.mark.skipif(_chrome() is None, reason="needs a headless Chrome/Chromium")
+def test_search_page_runs_under_production_csp_and_payload_does_not(live_csp_server, tmp_path):
+    chrome = _chrome()
+    # Control: the production CSP really blocks nonce-less inline script.
+    control = _render(chrome, f"{live_csp_server}/csp-control", tmp_path / "p0")
+    assert "<body>" in control and "data-ran" not in control
+
+    normal = _render(chrome, f"{live_csp_server}/search/web?q=weather", tmp_path / "p1")
+    assert "2 results" in normal                                   # the page's script executed
+    assert 'href="https://example.com/a"' in normal
+    assert "javascript:" not in normal.split('id="results"', 1)[1]  # non-http result URL not linked
+
+    hostile = _render(
+        chrome, f"{live_csp_server}/search/web?q={urllib.parse.quote(_PAYLOAD)}", tmp_path / "p2",
+    )
+    assert "2 results" in hostile                                  # search still ran with that query
+    assert hostile.split("<title>", 1)[1].split("</title>", 1)[0] != "PWNED"  # escaped text, not run
+    assert "data-pwned" not in hostile
diff --git a/tests/test_codeql_python_residual_followup.py b/tests/test_codeql_python_residual_followup.py
new file mode 100644
index 000000000..068d7c4a8
--- /dev/null
+++ b/tests/test_codeql_python_residual_followup.py
@@ -0,0 +1,260 @@
+"""Follow-up security fixes for the residual Python CodeQL lane (PR #6503).
+
+A. upload-reference scanners stay linear and match the regexes they replaced.
+B. /api/hwfit/* (SSH host probing, host path probing) is admin-only.
+C. IMAP/SMTP connections honour the outbound address policy, and the account
+   connection test never echoes a non-mail service's bytes.
+D. attachment extraction directories are per owner/account, not per folder/UID.
+"""
+
+import asyncio
+import contextlib
+import imaplib
+import re
+import smtplib
+import socket
+import ssl
+import time
+from email.mime.application import MIMEApplication
+from email.mime.multipart import MIMEMultipart
+from email.mime.text import MIMEText
+from types import SimpleNamespace
+
+import pytest
+
+# -- A. upload reference scanners ---------------------------------------------
+
+_HEX = "a" * 32
+_PDF_REF = re.compile(
+    r"<!--\s*pdf(?:_form)?_source\b[^>]*\bupload_id=[\"']([0-9a-fA-F]{32}(?:\.[A-Za-z0-9]+)?)[\"'][^>]*-->",
+    re.IGNORECASE,
+)
+_ATTACHMENT_REF = re.compile(
+    r"\[Attachment:[^\]\r\n]*\|\s*id=([0-9a-fA-F]{32}(?:\.[A-Za-z0-9]+)?)(?:\s*\||\s*\])",
+    re.IGNORECASE,
+)
+
+
+@pytest.mark.parametrize("text", [
+    f"<!-- pdf_source upload_id='{_HEX}' -->",
+    f"<!--PDF_FORM_SOURCE x upload_id=\"{_HEX}.pdf\" y-->",
+    f"<!-- pdf_source upload_id='{_HEX}' upload_id='{'b' * 32}' -->",
+    f"<!-- pdf_source upload_id='{_HEX}' ->",
+    f"<!-- pdf_sourceupload_id='{_HEX}' -->",
+    f"<!--pdf_source <!--pdf_source upload_id='{_HEX}'-->",
+    "<!-- pdf_source no id -->",
+])
+def test_pdf_source_ids_match_reference(text):
+    from src.upload_handler import _pdf_source_upload_ids
+
+    assert _pdf_source_upload_ids(text) == _PDF_REF.findall(text)
+
+
+@pytest.mark.parametrize("text", [
+    f"[Attachment: report.pdf | id={_HEX} | 12 KB]",
+    f"[attachment: a | b | id={_HEX}.txt]",
+    f"[Attachment: a | id={_HEX} | id={'b' * 32}]",
+    f"[Attachment: x |\nid={_HEX}]",
+    f"[Attachment: [Attachment: n | id={_HEX}]",
+    f"[Attachment: n | id={_HEX}x]",
+    "[Attachment: no id here]",
+])
+def test_attachment_reference_ids_match_reference(text):
+    from src.upload_handler import _attachment_reference_ids
+
+    assert _attachment_reference_ids(text) == _ATTACHMENT_REF.findall(text)
+
+
+@pytest.mark.parametrize("flood", [
+    "[attachment:" * 20_000,                 # CodeQL's reported shape (#615)
+    "[Attachment: a |" * 15_000,
+    "<!-- pdf_source upload_id=" * 9_000,    # same sink, other pattern
+    "<!--pdf_source " + f"upload_id='{_HEX}' " * 5_000 + "-->",
+])
+def test_internal_upload_id_extraction_is_linear(flood):
+    from src.upload_handler import extract_internal_upload_ids
+
+    started = time.perf_counter()
+    extract_internal_upload_ids(flood)
+    assert time.perf_counter() - started < 2.0
+
+
+# -- B. hwfit authorization -----------------------------------------------------
+
+def _hwfit_client(monkeypatch, *, auth_disabled=False):
+    from fastapi import FastAPI, Request
+    from fastapi.testclient import TestClient
+    import core.middleware as middleware
+    import services.hwfit.hardware as hardware
+    from routes.hwfit_routes import setup_hwfit_routes
+
+    probes = []
+    monkeypatch.setattr(middleware, "auth_disabled", lambda: auth_disabled)
+    monkeypatch.setattr(
+        hardware, "detect_system",
+        lambda **kwargs: probes.append(kwargs) or {"backend": "cpu_x86"},
+    )
+    app = FastAPI()
+    app.state.auth_manager = SimpleNamespace(is_configured=True, is_admin=lambda user: user == "root")
+
+    @app.middleware("http")
+    async def _user(request: Request, call_next):
+        request.state.current_user = request.headers.get("x-test-user")
+        return await call_next(request)
+
+    app.include_router(setup_hwfit_routes())
+    return TestClient(app), probes
+
+
+@pytest.mark.parametrize("path", [
+    "/api/hwfit/system?host=10.0.0.5&ssh_port=2222",
+    "/api/hwfit/models?host=169.254.169.254",
+    "/api/hwfit/profiles?model_path=/etc&host=",
+    "/api/hwfit/image-models?host=internal-db",
+])
+def test_hwfit_rejects_non_admin_before_any_probe(monkeypatch, path):
+    client, probes = _hwfit_client(monkeypatch)
+    response = client.get(path, headers={"x-test-user": "alice"})
+    assert response.status_code == 403
+    assert probes == []
+
+
+def test_hwfit_allows_admin_and_single_user(monkeypatch):
+    client, probes = _hwfit_client(monkeypatch)
+    assert client.get("/api/hwfit/system", headers={"x-test-user": "root"}).status_code == 200
+    client, probes = _hwfit_client(monkeypatch, auth_disabled=True)
+    assert client.get("/api/hwfit/system", headers={"x-test-user": "anyone"}).status_code == 200
+    assert probes
+
+
+# -- C. mail server address policy and test-connection errors -------------------
+
+def test_imap_and_smtp_helpers_refuse_metadata_hosts_before_any_socket(monkeypatch):
+    """Real helper paths (no stdlib patching): the policy rejects a literal
+    metadata address before a socket is even created. Policy matrix and DNS
+    rebinding coverage live in test_codeql_python_residual_closure.py."""
+    import routes.email.email_helpers as helpers
+
+    monkeypatch.delenv("EMAIL_BLOCK_PRIVATE_IPS", raising=False)
+    with pytest.raises(helpers.MailServerAddressBlocked):
+        helpers._open_imap_connection("169.254.169.254", 993, starttls=False, owner="alice")
+    with pytest.raises(helpers.MailServerAddressBlocked):
+        helpers._send_smtp_message(
+            {"smtp_host": "169.254.169.254", "smtp_port": 587, "owner": "alice"}, "a@b", ["c@d"], "x",
+        )
+
+
+@pytest.mark.parametrize("error,expected,leak", [
+    (imaplib.IMAP4.abort("unexpected response: b'SSH-2.0-OpenSSH_9.6 internal-db'"),
+     "IMAP server did not respond like an IMAP server", "OpenSSH"),
+    (smtplib.SMTPConnectError(554, b"-ERR redis 7.2 internal-cache"),
+     "SMTP server did not respond like an SMTP server", "redis"),
+    (smtplib.SMTPServerDisconnected("Connection unexpectedly closed: HTTP/1.1 400"),
+     "SMTP server did not respond like an SMTP server", "HTTP/1.1"),
+    (ConnectionRefusedError(111, "Connection refused 10.0.0.5:6379"), "IMAP connection refused", "6379"),
+    (socket.timeout("timed out"), "IMAP connection timed out", "10.0"),
+    (ssl.SSLError(1, "[SSL: WRONG_VERSION_NUMBER] banner: nginx"),
+     "IMAP TLS handshake failed; check the port and security setting", "nginx"),
+])
+def test_connection_test_errors_never_echo_peer_bytes(error, expected, leak):
+    from routes.email.email_helpers import _mail_connection_test_error
+
+    protocol = expected.split()[0]
+    message = _mail_connection_test_error(protocol, "10.0.0.5", error)
+    assert message == expected
+    assert leak not in message
+
+
+def test_connection_test_keeps_mail_server_auth_responses():
+    from routes.email.email_helpers import _mail_connection_test_error
+
+    assert _mail_connection_test_error(
+        "IMAP", "imap.example.com", imaplib.IMAP4.error("[AUTHENTICATIONFAILED] Invalid credentials"),
+    ) == "[AUTHENTICATIONFAILED] Invalid credentials"
+    microsoft = _mail_connection_test_error(
+        "SMTP", "smtp.office365.com",
+        smtplib.SMTPAuthenticationError(535, b"5.7.139 Authentication unsuccessful"),
+    )
+    assert "Microsoft no longer accepts" in microsoft
+
+
+def test_account_connection_test_route_applies_policy_to_both_protocols(monkeypatch):
+    import routes.email_routes as email_routes
+
+    monkeypatch.delenv("EMAIL_BLOCK_PRIVATE_IPS", raising=False)
+    router = email_routes.setup_email_routes()
+    endpoint = next(
+        r.endpoint for r in router.routes
+        if r.path == "/api/email/accounts/test" and "POST" in getattr(r, "methods", set())
+    )
+
+    class _Request:
+        async def json(self):
+            return {
+                "imap_host": "169.254.169.254", "imap_port": 993, "imap_user": "u", "imap_password": "p",
+                "smtp_host": "169.254.169.254", "smtp_port": 587,
+            }
+
+    result = asyncio.run(endpoint(req=_Request(), owner="alice"))
+    policy = "server address is not allowed by this server's network policy"
+    assert result["ok"] is False
+    assert result["imap"]["error"] == f"IMAP {policy}"
+    assert result["smtp"]["error"] == f"SMTP {policy}"
+
+
+# -- D. per-owner/account attachment extraction -------------------------------
+
+def _message_with_attachment(body: bytes) -> bytes:
+    msg = MIMEMultipart()
+    msg.attach(MIMEText("see attached", "plain"))
+    part = MIMEApplication(body, Name="invoice.pdf")
+    part["Content-Disposition"] = 'attachment; filename="invoice.pdf"'
+    msg.attach(part)
+    return msg.as_bytes()
+
+
+def test_attachment_extract_dir_separates_owners_and_accounts(tmp_path, monkeypatch):
+    import routes.email.email_helpers as helpers
+
+    monkeypatch.setattr(helpers, "ATTACHMENTS_DIR", tmp_path)
+    alice = helpers.attachment_extract_dir("INBOX", "42", owner="alice", account_id="a1")
+    assert alice != helpers.attachment_extract_dir("INBOX", "42", owner="bob", account_id="a1")
+    assert alice != helpers.attachment_extract_dir("INBOX", "42", owner="alice", account_id="a2")
+    assert alice != helpers.attachment_extract_dir("INBOX/42", "", owner="alice", account_id="a1")
+    assert alice.parent == tmp_path.resolve()
+
+
+def test_two_users_same_folder_uid_cannot_overwrite_each_others_attachment(tmp_path, monkeypatch):
+    """Two principals, same INBOX UID 42, same attachment filename.
+
+    Before the fix both extractions landed in ATTACHMENTS_DIR/INBOX_42/, so
+    bob's request rewrote the file whose path alice's agent was about to read.
+    """
+    import routes.email.email_helpers as helpers
+    import routes.email_routes as email_routes
+
+    monkeypatch.setattr(helpers, "ATTACHMENTS_DIR", tmp_path)
+    mailboxes = {
+        "alice": _message_with_attachment(b"%PDF alice private invoice"),
+        "bob": _message_with_attachment(b"%PDF bob controlled content"),
+    }
+
+    @contextlib.contextmanager
+    def _fake_imap(account_id=None, owner=""):
+        yield SimpleNamespace(owner=owner, select=lambda *a, **k: ("OK", [b"1"]))
+
+    monkeypatch.setattr(email_routes, "_imap", _fake_imap)
+    monkeypatch.setattr(
+        email_routes, "_imap_uid_fetch",
+        lambda conn, uid, query: ("OK", [(b"42 (RFC822)", mailboxes[conn.owner])]),
+    )
+    router = email_routes.setup_email_routes()
+    endpoint = next(r.endpoint for r in router.routes if r.path == "/api/email/attachment-path/{uid}/{index}")
+
+    alice = asyncio.run(endpoint(uid="42", index=0, folder="INBOX", account_id=None, owner="alice"))
+    bob = asyncio.run(endpoint(uid="42", index=0, folder="INBOX", account_id=None, owner="bob"))
+
+    assert alice["filename"] == bob["filename"] == "invoice.pdf"
+    assert alice["path"] != bob["path"]
+    with open(alice["path"], "rb") as handle:
+        assert handle.read() == b"%PDF alice private invoice"
diff --git a/tests/test_codeql_python_residual_security.py b/tests/test_codeql_python_residual_security.py
new file mode 100644
index 000000000..314550ba0
--- /dev/null
+++ b/tests/test_codeql_python_residual_security.py
@@ -0,0 +1,164 @@
+"""Adversarial tests for the residual Python CodeQL fixes (PR #6503 lane).
+
+Covers py/reflective-xss (search page), py/path-injection (context_info host
+path oracle) and py/stack-trace-exposure (readiness, stream errors, task
+drafting).
+"""
+
+import asyncio
+import json
+import re
+from types import SimpleNamespace
+
+import pytest
+
+
+# -- py/reflective-xss: GET /search/web?q= ----------------------------------
+
+_XSS_QUERIES = [
+    '</script><script src="https://cdn.jsdelivr.net/gh/evil/x@1/p.js"></script>',
+    "</SCRIPT><img src=x onerror=alert(1)>",
+    "<!--<script>",
+    "a & b < c > d 
 \"quoted\" 'single'",
+]
+
+
+def _search_page(q):
+    from routes.search.search_routes import setup_search_routes
+
+    router = setup_search_routes(SimpleNamespace())
+    endpoint = next(r.endpoint for r in router.routes if r.path == "/search/web")
+    request = SimpleNamespace(state=SimpleNamespace(csp_nonce="n0nce"))
+    return asyncio.run(endpoint(request=request, q=q)).body.decode("utf-8")
+
+
+@pytest.mark.parametrize("q", _XSS_QUERIES)
+def test_search_page_query_cannot_break_out_of_inline_script(q):
+    page = _search_page(q)
+    script = page.split('<script nonce="n0nce">', 1)[1]
+    # The page's own closing tag is the only one; nothing from q survives raw.
+    assert script.lower().count("</script") == 1
+    assert "<!--" not in script
+    literal = re.search(r"const initialQuery = (.*?);\n", script).group(1)
+    assert "<" not in literal and ">" not in literal and "&" not in literal
+    # The JS string value is unchanged for the search itself.
+    assert json.loads(literal) == q.strip()
+
+
+# -- py/path-injection: /session/{id}/context_info?cwd= ----------------------
+
+def _context_info(monkeypatch, *, admin, cwd):
+    import routes.session_routes as routes
+    from fastapi import APIRouter
+
+    monkeypatch.setattr(routes, "_verify_session_owner", lambda *args: None)
+    monkeypatch.setattr("src.tool_security.blocked_tools_for_owner", lambda owner: set())
+    monkeypatch.setattr("src.tool_security.owner_is_admin_or_single_user", lambda owner: admin)
+    monkeypatch.setattr(routes, "router", APIRouter(prefix="/api"))
+    session = SimpleNamespace(endpoint_url="", model="", cwd="")
+    router = routes.setup_session_routes(SimpleNamespace(get_session=lambda sid: session), {})
+    endpoint = next(
+        r.endpoint for r in router.routes if r.path == "/api/session/{session_id}/context_info"
+    )
+    request = SimpleNamespace(state=SimpleNamespace(
+        api_token=False, api_token_owner=None, api_token_scopes=[], current_user="someone",
+    ))
+    return asyncio.run(endpoint(request, "session-1", cwd=cwd))
+
+
+def test_context_info_hides_host_paths_from_non_admin(monkeypatch, tmp_path):
+    (tmp_path / "AGENTS.md").write_text("x", encoding="utf-8")
+    result = _context_info(monkeypatch, admin=False, cwd=str(tmp_path))
+    assert result["agents_md"] == []
+    assert result["workspace"]["exists_in_backend"] is False
+
+
+def test_context_info_still_reports_host_paths_for_admin(monkeypatch, tmp_path):
+    (tmp_path / "AGENTS.md").write_text("x", encoding="utf-8")
+    result = _context_info(monkeypatch, admin=True, cwd=str(tmp_path))
+    assert {"path": str(tmp_path / "AGENTS.md"), "source": "workspace"} in result["agents_md"]
+    assert result["workspace"]["exists_in_backend"] is True
+
+
+# -- py/stack-trace-exposure ---------------------------------------------------
+
+_SECRET = "postgresql://odysseus:hunter2@10.0.0.5/prod /srv/odysseus/data"
+
+
+def test_readiness_does_not_return_raw_database_error(monkeypatch):
+    import core.database as database
+    from src.readiness import check_readiness
+
+    class _Engine:
+        def connect(self):
+            raise RuntimeError(_SECRET)
+
+    monkeypatch.setattr(database, "engine", _Engine())
+    result = check_readiness()
+    db_check = result["checks"]["database"]
+    assert db_check == {"ok": False, "error_type": "RuntimeError"}
+    assert "hunter2" not in json.dumps(result)
+    assert result["ready"] is False
+
+
+def test_readiness_does_not_return_raw_data_dir_error(monkeypatch, tmp_path):
+    import core.constants as constants
+    from src.readiness import check_readiness
+
+    blocker = tmp_path / "not-a-dir"
+    blocker.write_text("file, not a directory", encoding="utf-8")
+    monkeypatch.setattr(constants, "DATA_DIR", str(blocker / "data"))
+    result = check_readiness()
+    data_check = result["checks"]["data_dir"]
+    assert data_check["ok"] is False
+    assert set(data_check) == {"ok", "error_type"}
+    assert str(tmp_path) not in json.dumps(result)
+
+
+def test_stream_failure_message_is_generic():
+    from src.llm_core import _stream_failure_message
+
+    assert _stream_failure_message(RuntimeError(_SECRET)) == "Model stream failed (RuntimeError)"
+
+
+def test_catch_all_stream_error_events_do_not_embed_exception_text():
+    from pathlib import Path
+
+    source = (Path(__file__).resolve().parents[1] / "src/llm_core.py").read_text(encoding="utf-8")
+    assert '{"error": str(e), "status": 502' not in source
+
+
+def _parse_task(monkeypatch, exc):
+    from fastapi import HTTPException  # noqa: F401  (raised by callers below)
+    from unittest.mock import MagicMock
+    import routes.task.task_routes as task_routes
+    import src.endpoint_resolver as resolver
+    import src.llm_core as llm_core
+
+    async def _boom(*args, **kwargs):
+        raise exc
+
+    monkeypatch.setattr(resolver, "resolve_endpoint", lambda *a, **k: ("http://llm", "m", {}))
+    monkeypatch.setattr(llm_core, "llm_call_async", _boom)
+    router = task_routes.setup_task_routes(MagicMock())
+    endpoint = next(r.endpoint for r in router.routes if r.path == "/api/tasks/parse")
+
+    class _Request:
+        state = SimpleNamespace(current_user="alice")
+
+        async def json(self):
+            return {"description": "every day at 9 summarize the news"}
+
+    return asyncio.run(endpoint(_Request()))
+
+
+def test_parse_task_hides_unexpected_exception_text(monkeypatch):
+    result = _parse_task(monkeypatch, RuntimeError(_SECRET))
+    assert result == {"success": False, "message": "Could not draft a task (RuntimeError)"}
+
+
+def test_parse_task_keeps_curated_upstream_http_error(monkeypatch):
+    from fastapi import HTTPException
+
+    result = _parse_task(monkeypatch, HTTPException(401, "Upstream rejected the API key"))
+    assert result == {"success": False, "message": "Upstream rejected the API key"}
diff --git a/tests/test_email_imap_timeout.py b/tests/test_email_imap_timeout.py
index c170106c1..94e7133d2 100644
--- a/tests/test_email_imap_timeout.py
+++ b/tests/test_email_imap_timeout.py
@@ -26,7 +26,7 @@ class _FakeSock:
 class _FakeIMAP:
     calls = []
 
-    def __init__(self, host, port, timeout=None):
+    def __init__(self, host, port, timeout=None, **_policy):
         self.host = host
         self.port = port
         self.timeout = timeout
@@ -60,8 +60,8 @@ def test_open_imap_connection_uses_shared_timeout_for_implicit_ssl(monkeypatch):
     import routes.email_helpers as helpers
 
     _FakeIMAP.calls = []
-    monkeypatch.setattr(helpers.imaplib, "IMAP4", _FakeIMAP)
-    monkeypatch.setattr(helpers.imaplib, "IMAP4_SSL", _FakeIMAPSSL)
+    monkeypatch.setattr(helpers, "_PolicyIMAP4", _FakeIMAP)
+    monkeypatch.setattr(helpers, "_PolicyIMAP4_SSL", _FakeIMAPSSL)
 
     conn = _open_imap_connection("imap.one.com", 993, starttls=False)
 
@@ -75,8 +75,8 @@ def test_open_imap_connection_supports_starttls(monkeypatch):
     import routes.email_helpers as helpers
 
     _FakeIMAP.calls = []
-    monkeypatch.setattr(helpers.imaplib, "IMAP4", _FakeIMAP)
-    monkeypatch.setattr(helpers.imaplib, "IMAP4_SSL", _FakeIMAPSSL)
+    monkeypatch.setattr(helpers, "_PolicyIMAP4", _FakeIMAP)
+    monkeypatch.setattr(helpers, "_PolicyIMAP4_SSL", _FakeIMAPSSL)
 
     _open_imap_connection("imap.local", 143, starttls=True)
 
@@ -99,7 +99,7 @@ async def test_account_config_uses_shared_imap_timeout(monkeypatch):
         def logout(self):
             captured["logout"] = True
 
-    def fake_open(host, port, *, starttls, timeout):
+    def fake_open(host, port, *, starttls, timeout, **_policy):
         captured["open"] = (host, port, starttls, timeout)
         return _Conn()
 
diff --git a/tests/test_email_send_only_no_inbox.py b/tests/test_email_send_only_no_inbox.py
index 1af014aae..c7ed2eefb 100644
--- a/tests/test_email_send_only_no_inbox.py
+++ b/tests/test_email_send_only_no_inbox.py
@@ -64,7 +64,7 @@ def test_imap_connect_with_host_still_connects(monkeypatch):
         def login(self, user, password):
             opened["login"] = (user, password)
 
-    def _fake_open(host, port, *, starttls, timeout):
+    def _fake_open(host, port, *, starttls, timeout, **_policy):
         opened["host"] = host
         return _FakeConn()
 
diff --git a/tests/test_email_smtp_security.py b/tests/test_email_smtp_security.py
index 590a5e60c..d64fbdf1e 100644
--- a/tests/test_email_smtp_security.py
+++ b/tests/test_email_smtp_security.py
@@ -12,7 +12,7 @@ from routes.email_helpers import _send_smtp_message
 class _FakeSMTP:
     calls = []
 
-    def __init__(self, host, port, timeout=None):
+    def __init__(self, host, port, timeout=None, **_policy):
         self.host = host
         self.port = port
         self.timeout = timeout
@@ -54,8 +54,8 @@ def test_send_smtp_message_supports_plain_smtp(monkeypatch):
     import routes.email_helpers as helpers
 
     _FakeSMTP.calls = []
-    monkeypatch.setattr(helpers.smtplib, "SMTP", _FakeSMTP)
-    monkeypatch.setattr(helpers.smtplib, "SMTP_SSL", _FakeSMTPSSL)
+    monkeypatch.setattr(helpers, "_PolicySMTP", _FakeSMTP)
+    monkeypatch.setattr(helpers, "_PolicySMTP_SSL", _FakeSMTPSSL)
 
     _send_smtp_message(_cfg("none"), "from@example.com", ["to@example.com"], "hello")
 
@@ -68,8 +68,8 @@ def test_send_smtp_message_supports_explicit_starttls(monkeypatch):
     import routes.email_helpers as helpers
 
     _FakeSMTP.calls = []
-    monkeypatch.setattr(helpers.smtplib, "SMTP", _FakeSMTP)
-    monkeypatch.setattr(helpers.smtplib, "SMTP_SSL", _FakeSMTPSSL)
+    monkeypatch.setattr(helpers, "_PolicySMTP", _FakeSMTP)
+    monkeypatch.setattr(helpers, "_PolicySMTP_SSL", _FakeSMTPSSL)
 
     _send_smtp_message(_cfg("starttls", port=2525), "from@example.com", ["to@example.com"], "hello")
 
@@ -82,8 +82,8 @@ def test_send_smtp_message_defaults_587_to_starttls(monkeypatch):
     import routes.email_helpers as helpers
 
     _FakeSMTP.calls = []
-    monkeypatch.setattr(helpers.smtplib, "SMTP", _FakeSMTP)
-    monkeypatch.setattr(helpers.smtplib, "SMTP_SSL", _FakeSMTPSSL)
+    monkeypatch.setattr(helpers, "_PolicySMTP", _FakeSMTP)
+    monkeypatch.setattr(helpers, "_PolicySMTP_SSL", _FakeSMTPSSL)
 
     cfg = _cfg("", port=587)
     _send_smtp_message(cfg, "from@example.com", ["to@example.com"], "hello")
@@ -96,8 +96,8 @@ def test_send_smtp_message_uses_ssl_when_configured(monkeypatch):
     import routes.email_helpers as helpers
 
     _FakeSMTP.calls = []
-    monkeypatch.setattr(helpers.smtplib, "SMTP", _FakeSMTP)
-    monkeypatch.setattr(helpers.smtplib, "SMTP_SSL", _FakeSMTPSSL)
+    monkeypatch.setattr(helpers, "_PolicySMTP", _FakeSMTP)
+    monkeypatch.setattr(helpers, "_PolicySMTP_SSL", _FakeSMTPSSL)
 
     _send_smtp_message(_cfg("ssl", port=465), "from@example.com", ["to@example.com"], "hello")
 
diff --git a/tests/test_email_test_connection_oauth.py b/tests/test_email_test_connection_oauth.py
index cc524d958..107a79fbb 100644
--- a/tests/test_email_test_connection_oauth.py
+++ b/tests/test_email_test_connection_oauth.py
@@ -89,8 +89,8 @@ async def test_test_connection_oauth_account_uses_xoauth2_for_imap_and_smtp():
 
     with mock.patch("core.database.SessionLocal", Factory), \
          mock.patch("routes.email_routes._open_imap_connection", return_value=mock_imap_conn), \
-         mock.patch("routes.email_routes.smtplib.SMTP", return_value=mock_smtp_conn), \
-         mock.patch("routes.email_routes.smtplib.SMTP_SSL", return_value=mock_smtp_conn), \
+         mock.patch("routes.email_routes._PolicySMTP", return_value=mock_smtp_conn), \
+         mock.patch("routes.email_routes._PolicySMTP_SSL", return_value=mock_smtp_conn), \
          mock.patch("routes.email_routes._get_valid_google_token", return_value="ya29.live") as token_getter:
         result = await test_conn(req=_FakeReq(), owner="alice")
 
@@ -141,8 +141,8 @@ async def test_test_connection_password_account_still_uses_login():
 
     with mock.patch("core.database.SessionLocal", Factory), \
          mock.patch("routes.email_routes._open_imap_connection", return_value=mock_imap_conn), \
-         mock.patch("routes.email_routes.smtplib.SMTP", return_value=mock_smtp_conn), \
-         mock.patch("routes.email_routes.smtplib.SMTP_SSL", return_value=mock_smtp_conn):
+         mock.patch("routes.email_routes._PolicySMTP", return_value=mock_smtp_conn), \
+         mock.patch("routes.email_routes._PolicySMTP_SSL", return_value=mock_smtp_conn):
         result = await test_conn(req=_FakeReq(), owner="alice")
 
     assert result["ok"] is True
@@ -187,8 +187,8 @@ async def test_test_connection_rejects_non_google_hosts_before_oauth_auth():
 
     with mock.patch("core.database.SessionLocal", Factory), \
          mock.patch("routes.email_routes._open_imap_connection") as open_imap, \
-         mock.patch("routes.email_routes.smtplib.SMTP") as open_smtp, \
-         mock.patch("routes.email_routes.smtplib.SMTP_SSL") as open_smtp_ssl, \
+         mock.patch("routes.email_routes._PolicySMTP") as open_smtp, \
+         mock.patch("routes.email_routes._PolicySMTP_SSL") as open_smtp_ssl, \
          mock.patch("routes.email_routes._get_valid_google_token") as token_getter:
         result = await test_conn(req=_FakeReq(), owner="alice")
 
@@ -238,8 +238,8 @@ async def test_test_connection_rejects_insecure_oauth_transports_before_auth():
 
     with mock.patch("core.database.SessionLocal", Factory), \
          mock.patch("routes.email_routes._open_imap_connection") as open_imap, \
-         mock.patch("routes.email_routes.smtplib.SMTP") as open_smtp, \
-         mock.patch("routes.email_routes.smtplib.SMTP_SSL") as open_smtp_ssl, \
+         mock.patch("routes.email_routes._PolicySMTP") as open_smtp, \
+         mock.patch("routes.email_routes._PolicySMTP_SSL") as open_smtp_ssl, \
          mock.patch("routes.email_routes._get_valid_google_token") as token_getter:
         result = await test_conn(req=_FakeReq(), owner="alice")
 
@@ -336,10 +336,10 @@ async def test_test_connection_verifies_imap_tls_before_loading_oauth_token(
              "routes.email_routes.ssl.create_default_context",
              return_value=context,
          ), mock.patch(
-             "routes.email_helpers.imaplib.IMAP4",
+             "routes.email_helpers._PolicyIMAP4",
              return_value=starttls_conn,
          ) as imap_cls, mock.patch(
-             "routes.email_helpers.imaplib.IMAP4_SSL",
+             "routes.email_helpers._PolicyIMAP4_SSL",
              side_effect=ssl.SSLCertVerificationError("untrusted certificate"),
          ) as imap_ssl_cls, mock.patch(
              "routes.email_routes._get_valid_google_token"
@@ -412,10 +412,10 @@ async def test_test_connection_verifies_smtp_tls_before_loading_oauth_token(
              "routes.email_routes.ssl.create_default_context",
              return_value=context,
          ), mock.patch(
-             "routes.email_routes.smtplib.SMTP",
+             "routes.email_routes._PolicySMTP",
              return_value=starttls_smtp,
          ) as smtp_cls, mock.patch(
-             "routes.email_routes.smtplib.SMTP_SSL",
+             "routes.email_routes._PolicySMTP_SSL",
              side_effect=ssl.SSLCertVerificationError("untrusted certificate"),
          ) as smtp_ssl_cls, mock.patch(
              "routes.email_routes._get_valid_google_token"
diff --git a/tests/test_imap_leak_fixes.py b/tests/test_imap_leak_fixes.py
index 520a50e1e..83879d077 100644
--- a/tests/test_imap_leak_fixes.py
+++ b/tests/test_imap_leak_fixes.py
@@ -281,7 +281,7 @@ def test_open_imap_connection_shuts_down_on_starttls_failure(monkeypatch):
     ))
     conn.starttls = MagicMock(side_effect=RuntimeError("STARTTLS rejected"))
 
-    monkeypatch.setattr(helpers.imaplib, "IMAP4", lambda *a, **kw: conn)
+    monkeypatch.setattr(helpers, "_PolicyIMAP4", lambda *a, **kw: conn)
 
     raised = False
     try:
diff --git a/tests/test_notes_reminder_temporal_redos.py b/tests/test_notes_reminder_temporal_redos.py
new file mode 100644
index 000000000..709aedbc4
--- /dev/null
+++ b/tests/test_notes_reminder_temporal_redos.py
@@ -0,0 +1,60 @@
+"""manage_notes reminder-time sniffing must stay linear (CodeQL py/polynomial-redos).
+
+`\\d{1,2}(?::\\d{2})?\\s*(?:am|pm)?\\s+today` let `\\s*` and `\\s+` split one
+whitespace run every possible way, so a digit followed by a long whitespace
+run in model-supplied note text was O(n^2). The rewrite groups the optional
+meridiem with its own whitespace: same language, one way to match.
+"""
+
+import json
+import sys
+import time
+import uuid
+
+import pytest
+
+from tests.helpers.import_state import clear_fake_database_modules
+from tests.helpers.sqlite_db import make_temp_sqlite
+
+clear_fake_database_modules()
+
+import core.database as cdb
+
+_TS, _ENGINE, _TMPDB = make_temp_sqlite(cdb.Base.metadata)
+
+
+@pytest.fixture(autouse=True)
+def _bind_temp_db(monkeypatch):
+    monkeypatch.setitem(sys.modules, "core.database", cdb)
+    parent = sys.modules.get("core")
+    if parent is not None:
+        monkeypatch.setattr(parent, "database", cdb, raising=False)
+    monkeypatch.setattr(cdb, "SessionLocal", _TS)
+    yield
+
+
+async def _add(content):
+    from src.tool_implementations import do_manage_notes
+
+    return await do_manage_notes(
+        json.dumps({"action": "add", "title": "remind me", "content": content}),
+        owner="tester-" + uuid.uuid4().hex[:6],
+    )
+
+
+async def test_reminder_time_sniffing_whitespace_flood_is_linear():
+    started = time.perf_counter()
+    res = await _add("remind 1" + "\t" * 40_000 + "x")
+    assert time.perf_counter() - started < 2.0
+    assert res.get("exit_code", 0) == 0, res
+
+
+async def test_reminder_time_sniffing_still_finds_time_first_phrases():
+    res = await _add("remind me to call mom, 9 pm tomorrow")
+    assert res.get("exit_code", 0) == 0, res
+    db = _TS()
+    try:
+        note = db.query(cdb.Note).filter(cdb.Note.id == res["note_id"]).first()
+        assert note is not None and "T21:00:00" in (note.due_date or ""), note and note.due_date
+    finally:
+        db.close()
diff --git a/tests/test_redos_residual_python.py b/tests/test_redos_residual_python.py
new file mode 100644
index 000000000..276c71059
--- /dev/null
+++ b/tests/test_redos_residual_python.py
@@ -0,0 +1,183 @@
+"""Regression tests for the residual py/polynomial-redos fixes (PR #6503 lane).
+
+Each rewritten matcher is pinned two ways:
+  * equivalence with the regex it replaced on ordinary inputs, and
+  * the CodeQL-reported adversarial shape completing within a loose budget
+    (the replaced regexes took seconds to tens of seconds on these sizes).
+"""
+
+import re
+import time
+from pathlib import Path
+
+import pytest
+
+from src.text_helpers import strip_closed_think_blocks
+
+_BUDGET_S = 2.0
+_ROOT = Path(__file__).resolve().parents[1]
+
+
+def _fast(fn, *args):
+    started = time.perf_counter()
+    result = fn(*args)
+    elapsed = time.perf_counter() - started
+    assert elapsed < _BUDGET_S, f"{getattr(fn, '__name__', fn)} took {elapsed:.2f}s"
+    return result
+
+
+# -- closed <think> blocks (skills_routes x4, memory_extractor.audit_memories) --
+
+_THINK_REF = re.compile(r"<think(?:ing)?>[\s\S]*?</think(?:ing)?>", re.I)
+
+
+@pytest.mark.parametrize("text", [
+    "",
+    "plain",
+    "<think>x</think>{\"ok\": true}",
+    "a<thinking>b</thinking>c<think>d</think>e",
+    "<think>a<think>nested</think>rest</think>",
+    "orphan</think> then <think>unclosed",
+    "<THINK>case</Thinking>kept",
+    "<think>\nmulti\nline\n</think>\n{}",
+])
+def test_strip_closed_think_blocks_matches_reference(text):
+    assert strip_closed_think_blocks(text) == _THINK_REF.sub("", text)
+
+
+def test_strip_closed_think_blocks_unclosed_opener_flood_is_linear():
+    flood = "<think>" * 40_000
+    assert _fast(strip_closed_think_blocks, flood) == flood
+
+
+def test_lazy_think_regex_is_gone_from_llm_review_parsers():
+    for rel in ("routes/skills_routes.py", "services/memory/memory_extractor.py"):
+        source = (_ROOT / rel).read_text(encoding="utf-8")
+        assert r"<think(?:ing)?>[\s\S]*?</think(?:ing)?>" not in source, rel
+
+
+# -- email compose markdown links (email_routes._md_to_email_html) -----------
+
+_LINK_REF = re.compile(r"\[([^\]]+)\]\((https?://[^)\s]+)\)")
+
+
+@pytest.mark.parametrize("text", [
+    "see [docs](https://example.com/a) and [b](http://x.y)",
+    "[a[b](http://x)",
+    "[]()[x](http://y)",
+    "[a](http://x [b c](http://y)",
+    "[a](http://)[b](https://z)",
+    "[a](ftp://x) [b](https://ok)",
+    "[unterminated(http://x)",
+    "[t](http://u) tail ] [",
+])
+def test_md_links_to_html_matches_reference(text):
+    from routes.email.email_routes import _md_links_to_html
+
+    assert _md_links_to_html(text) == _LINK_REF.sub(r'<a href="\2">\1</a>', text)
+
+
+@pytest.mark.parametrize("flood", [
+    "[" + "[\\" * 40_000,          # CodeQL's reported shape
+    "[a](http://x" * 8_000,        # URL that never closes, repeated
+])
+def test_md_links_to_html_floods_are_linear(flood):
+    from routes.email.email_routes import _md_links_to_html
+
+    assert _fast(_md_links_to_html, flood) == flood
+
+
+def test_md_to_email_html_still_renders_and_escapes_links():
+    from routes.email.email_routes import _md_to_email_html
+
+    html = _md_to_email_html("**hi** [site](https://example.com/x)\n<script>")
+    assert '<a href="https://example.com/x">site</a>' in html
+    assert "<strong>hi</strong>" in html
+    assert "<script>" not in html
+
+
+# -- PDF URL detection (chat_routes._prefers_structured_document_tools) ------
+
+_PDF_REF = re.compile(r"https?://[^\s]+(?:\.pdf\b|/pdf/)", re.I)
+
+
+@pytest.mark.parametrize("text", [
+    "read https://arxiv.org/pdf/2401.0001 please",
+    "https://x.org/paper.PDF",
+    "https://x.org/paper.pdfx",
+    "xhttps://a/b.pdf",
+    "http:///pdf/",
+    "http://a
.pdf",
+    "no links here.pdf",
+    "https://a/b http://c.pdf",
+])
+def test_mentions_pdf_url_matches_reference(text):
+    from routes.chat_routes import _mentions_pdf_url
+
+    assert _mentions_pdf_url(text) is bool(_PDF_REF.search(text))
+
+
+def test_mentions_pdf_url_scheme_flood_is_linear():
+    from routes.chat_routes import _prefers_structured_document_tools
+
+    assert _fast(_prefers_structured_document_tools, "http://" * 8_000) is False
+
+
+# -- chat_helpers persistence cleanup ----------------------------------------
+
+def test_clean_repeated_assistant_content_trailing_think_closer():
+    from routes.chat_helpers import clean_repeated_assistant_content
+
+    prose = "word " * 30 + "done"  # past the 120-char edge-closer window
+    assert clean_repeated_assistant_content(prose + "  </think>  ") == prose
+    whitespace_run = "a" + "\t" * 80_000 + "x"
+    assert _fast(clean_repeated_assistant_content, whitespace_run) == whitespace_run
+
+
+@pytest.mark.parametrize("text,expected", [
+    ("The user wants a hi.\n\n<think>Hey there!</think>",
+     "<think>The user wants a hi.</think>\nHey there!"),
+    ("I should greet.\n<thinking>  Hello  ", "<think>I should greet.</think>\nHello"),
+    ("Plain answer <think>x</think>", "Plain answer <think>x</think>"),
+])
+def test_normalize_thinking_garbled_tags_unchanged(text, expected):
+    from routes.chat_helpers import _normalize_thinking
+
+    assert _normalize_thinking(text) == expected
+
+
+@pytest.mark.parametrize("flood", [
+    "a" + "\n" * 80_000 + "x",
+    "The user x\n<think>" + "\t" * 80_000 + "x",
+])
+def test_normalize_thinking_floods_are_linear(flood):
+    from routes.chat_helpers import _normalize_thinking
+
+    _fast(_normalize_thinking, flood)
+
+
+# -- calendar natural-language datetimes (GET /events, POST /events) ---------
+
+def test_calendar_time_first_phrases_still_parse():
+    from routes.calendar_routes import _parse_dt, parse_due_for_user
+
+    parsed = _parse_dt("3pm tomorrow")
+    assert (parsed.hour, parsed.minute) == (15, 0)
+    assert "T09:00:00" in parse_due_for_user("9 a.m today")
+    assert "T23:00:00" in parse_due_for_user("11pm tonight")
+
+
+@pytest.mark.parametrize("payload", [
+    "a" + "\t" * 80_000 + "x",       # CodeQL's reported shape (time-first regex)
+    "a" + "\t" * 80_000 + "m",       # am/pm normaliser on the same input
+])
+def test_calendar_parsers_whitespace_flood_is_linear(payload):
+    from routes.calendar_routes import _parse_dt, parse_due_for_user
+
+    for fn in (_parse_dt, parse_due_for_user):
+        started = time.perf_counter()
+        try:
+            fn(payload)
+        except Exception:
+            pass  # unparseable is fine; only the time matters here
+        assert time.perf_counter() - started < _BUDGET_S, fn.__name__
diff --git a/tests/test_security_regressions.py b/tests/test_security_regressions.py
index 09142526d..fe63ccecd 100644
--- a/tests/test_security_regressions.py
+++ b/tests/test_security_regressions.py
@@ -984,7 +984,7 @@ def test_attachment_extract_dir_stays_contained(folder, uid):
     """User-controlled folder/uid must never escape ATTACHMENTS_DIR — pins the
     fix for the attachment-extraction path traversal."""
     aed, base = _import_attachment_extract_dir()
-    target = aed(folder, uid)
+    target = aed(folder, uid, owner="../../owner", account_id="../acct")
     base_r = base.resolve()
     assert target == base_r or base_r in target.parents
     # exactly one extra path segment, and no `..` component survived
@@ -992,9 +992,11 @@ def test_attachment_extract_dir_stays_contained(folder, uid):
     assert ".." not in rel.parts
 
 
-def test_attachment_extract_dir_normal_inputs_unchanged():
+def test_attachment_extract_dir_is_stable_single_segment_per_scope():
     aed, base = _import_attachment_extract_dir()
-    assert aed("INBOX", "123") == base.resolve() / "INBOX_123"
+    target = aed("INBOX", "123", owner="alice", account_id="acct-1")
+    assert target == aed("INBOX", "123", owner="alice", account_id="acct-1")
+    assert target.parent == base.resolve()
 
 
 def test_diagnostics_routes_are_admin_gated():