{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-56104: Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-56104","status":"final","version":"1","initial_release_date":"2026-06-22T14:17:52.640Z","current_release_date":"2026-06-23T14:42:38.931Z","revision_history":[{"date":"2026-06-22T14:17:52.640Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-56104 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-56104"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-56104"},{"category":"external","summary":"Release Notes","url":"https://github.com/Chainlit/chainlit/releases/tag/2.10.1"},{"category":"external","summary":"Pull Request","url":"https://github.com/Chainlit/chainlit/pull/2857"},{"category":"external","summary":"Patch Commit","url":"https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f"},{"category":"external","summary":"vulncheck.com","url":"https://www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration"}]},"product_tree":{"branches":[{"category":"vendor","name":"Chainlit","branches":[{"category":"product_name","name":"chainlit","branches":[{"category":"product_version_range","name":"<2.10.1","product":{"name":"Chainlit chainlit <2.10.1","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:chainlit:chainlit:*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-56104","title":"Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"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","baseScore":8.8,"baseSeverity":"HIGH"},"products":["CSAFPID-1"]}],"remediations":[{"category":"vendor_fix","details":"Update to a fixed version: 2.10.1.","product_ids":["CSAFPID-1"],"url":"https://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f"}]}]}