Listing a user's folders re-checks which entries they may still see, and it resolved their group membership again for every folder, then again inside the collection and note branches for every entry. A comment in that helper claims one membership fetch for the whole listing, but the caller invokes it once per folder, so the claim never held.
The listing now resolves membership once, and only when some folder actually carries entries, then threads it through the file, collection and note checks. Callers that do not supply it are unchanged and still resolve for themselves.
Measured with twenty folders holding six files, two knowledge bases and two notes each: 245 queries and ~145 ms before, 186 and ~117 ms after. The folders returned, and the entries the integrity pass writes back, are unchanged. That was checked against entries the caller owns, entries shared through a group, entries shared with nobody, another user's files, and an unrecognised entry type.
Checking whether a user may reach a file loaded and validated every workspace model that user can access, then scanned each model's knowledge list in Python for one file id. Folder listings run that check once per file, so opening a folder of twenty files rebuilt the whole accessible-model set twenty times, and the same check sits on every retrieval and download path.
The lookup now runs the other way round: the database returns the models that attach the file, and only those are access-checked. The text match on the metadata column is a prefilter and the knowledge entries still decide, so a file id that merely appears in a description grants nothing; file ids are server-generated uuids, so the match can only be too wide, never too narrow.
Measured with 500 accessible workspace models: a single check drops from 9 queries and ~20 ms to 6 and ~2.6 ms, and a twenty-file folder listing from 180 queries and ~680 ms to 120 and ~56 ms. A 72-case matrix over owner, public, direct-user and group grants, for both read and write, returns exactly what it returned before, and write still requires the model owner to own the file. The check also no longer writes to the database while answering a read-only question.
GLOBAL_LOG_LEVEL defaults to INFO, so every log.debug(...) in the backend is discarded, but the message is built first: 187 call sites interpolate their payload into an f-string before the logging call runs, so the work happens on every request and the result is thrown away. The worst one sits in process_chat_payload and stringifies the whole request body, full conversation history included, once per chat completion.
That one line with DEBUG disabled, CPython 3.12:
| conversation | payload | before | after |
| ------------ | ------- | -------- | ------- |
| 4 messages | 1.2 kB | 3.4 us | 0.07 us |
| 20 messages | 17 kB | 24.8 us | 0.07 us |
| 60 messages | 123 kB | 216.6 us | 0.07 us |
The lazy form log.debug('form_data: %s', form_data) hands the payload to record.getMessage(), which the InterceptHandler only reaches once a record has passed the level check. With DEBUG enabled the emitted lines are byte-identical, f'{x=}' sites included: those map to %r. MistralLoader._debug_log callers get the same treatment, since that wrapper already forwards *args.
get_accessible_folder_files is the server-side filter that reduces a folder's attached-knowledge list (and, once #26723 lands, a direct model's) to the entries the caller may read, before that list is handed to the builtin knowledge tools as `__model_knowledge__`. It validated `file` and `collection` entries but passed `note` entries through unchecked (they fell into the `else` keep-as-is branch), even though notes are a first-class attached-knowledge type that flows through this list.
No current caller is exploitable, because every note consumer (`query_knowledge_files`, `view_note`, and the legacy retrieval path) independently re-checks note access before returning content. But relying on each consumer to remember that check is exactly the fragility this helper exists to remove, and the same `_has_read_access_to_file` membership short-circuit that makes an unvalidated `file` entry dangerous would turn any future note path that trusts list membership into an IDOR. Validate notes here so the filter enforces its own contract instead of leaning on downstream re-checks.
A note entry is now kept only when the caller owns it or holds a read grant. Notes are private by default and carry no self-grant, so ownership is checked explicitly alongside the grant lookup. Admins still bypass all checks and genuinely unknown types are still kept as-is.
Related: #26723
has_access_to_file runs for every non-owner file GET, per RAG file check and per shared-chat or model-attached file. Its final step called Models.get_models_by_user_id, which issued one grant query per non-owned workspace model, so a single file check on an instance with M workspace models cost M grant queries plus a group query, with the deny path always paying full price. Its collection_name step listed every knowledge base the user can access (itself one grant query per knowledge base) just to scan the list for one id. And get_accessible_folder_files repeated the whole pipeline per folder entry, refetching the caller's group memberships every time.
Three changes, all using parameters and helpers that already exist:
- Models.get_models_by_user_id resolves grants for all non-owned models in one get_accessible_resource_ids call and accepts prefetched user_group_ids.
- The collection_name check fetches the one referenced knowledge base and performs a single owner-or-grant check with the already-resolved group ids, preserving the write-requires-owner guard exactly (including its short-circuit before any grant query).
- get_accessible_folder_files resolves group ids once and threads them through every per-entry check.
Benchmark:
| metric | before | after |
| --- | --- | --- |
| filter loop CPU, 300 workspace models (queries stubbed) | 47 us | 19 us |
| grant queries per file-access check, M workspace models | M | 1 |
| group membership queries per folder listing, F files | F | 1 |
The stubbed CPU row understates the win: each removed query in the other two rows was a real database round trip.
Functionally verified with stubbed accessors: owned plus granted models are returned with owned ids excluded from the batch query; model-attached file access resolves through the batched path; the collection_name path does one KB fetch and one grant check with no full listing; a missing KB falls through; write access via a KB still requires the KB owner to own the file and short-circuits before the grant query; folder listings fetch groups exactly once.
has_access_to_file() derives file access from the objects a file is attached to
(knowledge bases, workspace models). Those branches returned True for any access_type
whenever the user held that permission on the object, write/delete included. Since a
user can create their own KB or model and attach any file they can merely READ (KB
attach and the model meta.knowledge validator both gate on read access only), a user
with read access to a victim file could launder it into write/delete: attach it to an
object they own, then rename, overwrite or delete it via the write-gated file routes
(POST /files/{id}/rename, /data/content/update, DELETE /files/{id}). This is the
residual of GHSA-vjqm-6gcc-62cr (CVE-2026-54012) left open by the read-only attach
validator (CWE-863).
An object now confers write/delete on a file only when the object's owner owns that
file, so delegation originates from the file's own owner. Read is unchanged (RAG and
shared-object reads still work), and legitimate delegation is preserved: a write grant
on an object whose owner owns the attached file still confers write. Applied to all
three object branches: knowledge base, file home collection, and workspace model.
Co-authored-by: rexpository <30176934+rexpository@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
has_access_to_file granted access whenever the file was attached to a
shared chat the user could read, ignoring the requested access_type. A
read-only shared-chat recipient therefore satisfied write and delete
checks and could delete or mutate the chat owner's attached file. Gate
the shared-chat branch on read access, matching the channels branch
directly above it.
Co-authored-by: oxsignal <oxsignal@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Classic298