{"id":"CVE-2026-56104","aliases":["GHSA-c39v-8hrw-h448","PYSEC-2026-4028"],"url":"https://o3.security/vulnerability/CVE-2026-56104","summary":"Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration","details":"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.","published":"2026-06-22T14:17:52.640Z","modified":"2026-10-21T02:58:40.866107450Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"chainlit","fixedVersion":"2.10.1"}],"fix":{"url":"https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f","label":"Chainlit/chainlit@5effb66"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56104.json"},{"type":"ADVISORY","url":"https://github.com/Chainlit/chainlit/releases/tag/2.10.1"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56104"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration"},{"type":"REPORT","url":"https://github.com/Chainlit/chainlit/pull/2857"},{"type":"FIX","url":"https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f"},{"type":"PACKAGE","url":"https://github.com/Chainlit/chainlit"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:58:40.866107450Z"}}