The synchronous llm_call() runs in FastAPI's threadpool (sync route
handlers such as POST /sessions/auto-sort), while llm_call_async() runs
on the event loop. Both mutate the module-level _response_cache,
_host_fails and _dead_hosts dicts, so these are touched from multiple OS
threads concurrently. Two races result:
- _set_cached_response() snapshots 64 keys then deletes them with
`del _response_cache[key]`; if another thread evicts the same key
first, the del raises KeyError mid-eviction. Switched to
pop(key, None).
- _mark_host_dead() does get()+1+set() on _host_fails with no lock, so
concurrent connect failures lose increments and a genuinely dead host
can stay under its cooldown threshold. Guarded the host-health maps
with a threading.Lock (also applied to _is_host_dead / _clear_host_dead
for consistent reads).
Adds tests/test_llm_core_concurrency.py with deterministic regression
tests (phantom snapshot key for the eviction race; a slow-read dict that
forces the lost-update window for the counter). Both fail on the
unpatched code and pass with the fix.
The email reader folds quoted history into <details> summaries via
`_foldSummary()` (static/js/emailLibrary/signatureFold.js), which builds a
sender/date "meta" chip into the summary HTML and assigns it to innerHTML.
The server-side thread parser (`_extract_quote_meta`,
src/email_thread_parser.py) strips tags but then un-escapes HTML entities
and preserves `<...>` patterns, and that raw meta reaches `_foldSummary`
unescaped via `_renderTurnsFromServer` (`t.meta`) — so an inbound email
whose quoted attribution contains `From: <img src=x onerror=...>`
runs script when the victim merely opens the message (stored XSS).
Make `_foldSummary` the single escaping chokepoint: escape `primary` and
`subMeta` with the module's existing `_esc`. The client-side
`_extractQuoteMeta` previously pre-escaped its output, and every consumer
of it routes through `_foldSummary`, so drop that now-redundant escaping to
avoid double-encoding (e.g. "Ben & Jerry" -> "Ben &amp; Jerry").
Verified (jsdom): server-raw and client-extracted malicious metas yield 0
live elements and 0 event-handler attributes; benign "Ben & Jerry" renders
single-escaped.
Co-authored-by: Claude <noreply@anthropic.com>
SurprisedDuck