CVSS 4.0
8.8 highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:NCVE-2026-86099
High (8.8). EPSS 0.6% chance of exploitation in the next 30 days.
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.
Severity
CVSS 3.1
8.2 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H- EPSS
- 0.6% chance of exploitation in the next 30 days; higher than 48% of CVEs (scores of 2026-10-31)
- CWE
- CWE-22
- Published
- Modified
- Record from
- the NVD, synced
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