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AI agent vulnerability · Chainlit

CVE-2026-56104: Chainlit contains a session hijacking vulnerability

criticalCVSS 4.0 9.1 · 3.1 7.4GHSA-c39v-8hrw-h448

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.

Published Jun 22, 2026 · Updated Sep 21, 2026

Affected packages

chainlit

Ecosystem
PyPI
Affected
< 2.10.1
Fixed in
2.10.1
Check
pip show chainlit

Advisory details

From the GitHub Advisory Database (CC BY 4.0).

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.

References

How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology

More Chainlit vulnerabilities

All Chainlit entries