CVE-2026-86099
Description
Chainlit through 2.12.0 fails to validate the client-supplied socket.io sessionId parameter, allowing unauthenticated attackers to traverse filesystem paths by injecting absolute or relative path sequences. Attackers can craft malicious sessionId values that escape the upload directory and recursively delete arbitrary directories accessible to the service process.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://github.com/Chainlit/chainlit
- https://github.com/Chainlit/chainlit/blob/2.12.0/backend/chainlit/session.py
- https://github.com/Chainlit/chainlit/blob/2.12.0/backend/chainlit/socket.py
- https://pypi.org/project/chainlit/
- https://www.vulncheck.com/advisories/chainlit-through-2.12.0-path-traversal-via-socket-io-sessionid
CWEs
CWE-22
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.