{"cve":"CVE-2026-56104","nvd":{"published":"2026-06-22T16:16:40.227","modified":"2026-10-08T16:17:21.397","status":"Deferred","description":"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.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N","score":8.8},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N","score":8.2},"cwes":["CWE-862"],"references":["https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f","https://github.com/Chainlit/chainlit/pull/2857","https://github.com/Chainlit/chainlit/releases/tag/2.10.1","https://www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:39:28.638635428+00:00"},"epss":{"cve":"CVE-2026-56104","score":0.00417,"percentile":0.35673,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-c39v-8hrw-h448","url":"https://osv.dev/vulnerability/GHSA-c39v-8hrw-h448","summary":"Chainlit contains a session hijacking vulnerability","modified":"2026-10-01T17:56:10.751822436Z","packages":[{"ecosystem":"PyPI","name":"chainlit","purl":"pkg:pypi/chainlit","ranges":["<2.10.1"],"fixed":["2.10.1"]}]},{"id":"PYSEC-2026-4028","url":"https://osv.dev/vulnerability/PYSEC-2026-4028","summary":"Chainlit contains a session hijacking vulnerability","modified":"2026-10-01T17:45:05.547351343Z","packages":[{"ecosystem":"PyPI","name":"chainlit","purl":"pkg:pypi/chainlit","ranges":["<2.10.1"],"fixed":["2.10.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}