chainlitGHSA-c39v-8hrw-h448
Chainlit contains a session hijacking vulnerability
Fix: upgrade to 2.10.1 or later
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.
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| chainlit PyPI | < 2.10.1 | 2.10.1 |
Details and references
- CVSS 3.1
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-862
- Also known as
- CVE-2026-56104, PYSEC-2026-4028
- nvd.nist.gov/vuln/detail/CVE-2026-56104
- github.com/Chainlit/chainlit/pull/2857
- github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f
- github.com/Chainlit/chainlit
- github.com/Chainlit/chainlit/releases/tag/2.10.1
- www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration