CVE-2026-56104
Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration
CVSS Score
7.4
EPSS Score
0.0%
EPSS Percentile
0th
Chainlit before 2.10.1 contains a session hijacking vulnerability that allows unauthenticated attackers to restore and inherit authenticated user sessions by presenting a valid sessionId during WebSocket session restoration without ownership verification. Attackers can exploit the restore_existing_session path to assume a victim's permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim.
| CWE | CWE-862 |
| Vendor | chainlit |
| Product | chainlit |
| Published | Jun 22, 2026 |
| Last Updated | Jun 22, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
Chainlit / chainlit
0 < 2.10.1
References
github.com: https://github.com/Chainlit/chainlit/releases/tag/2.10.1 github.com: https://github.com/Chainlit/chainlit/pull/2857 github.com: https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f vulncheck.com: https://www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration
Credits
Tanguy Snoeck