{"id":"CVE-2026-46355","summary":"BigBlueButton: Unauthenticated Session Hijack via Exposed /bigbluebutton/api/handleJoinExistingUser","details":"BigBlueButton is an open-source virtual classroom. Prior to 3.0.23, BigBlueButton exposed /bigbluebutton/api/handleJoinExistingUser through bigbluebutton-web/grails-app/controllers/org/bigbluebutton/web/controllers/ApiController.groovy. A requester able to supply an existingUserID for an active participant could reuse that participant's session and impersonate the participant in the same meeting because handleJoinExistingUser was a routable controller action rather than a private helper. This issue is fixed in version 3.0.23.","aliases":["GHSA-38fw-2gq7-ccgr"],"modified":"2026-08-27T11:31:13.364317963Z","published":"2026-08-20T21:34:40.529Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-287"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46355.json"},"references":[{"type":"WEB","url":"https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.23"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46355.json"},{"type":"ADVISORY","url":"https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-38fw-2gq7-ccgr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46355"},{"type":"FIX","url":"https://github.com/bigbluebutton/bigbluebutton/commit/972b04e474e195cbd708b5b3f0485fe528a1a85b"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/bigbluebutton/bigbluebutton","events":[{"introduced":"0"},{"fixed":"972b04e474e195cbd708b5b3f0485fe528a1a85b"},{"fixed":"d32178587c1e623be2b87992b109af4a86c7a95e"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"3.0.23"}]}}],"versions":["v3.0.22","v3.0.21","v3.0.20","v3.0.19","v3.0.18","v3.0.17","v3.0.16","v3.0.15","v3.0.14","v3.0.13","v3.0.12","v3.0.11","v3.0.8","v3.0.10","v3.0.9","v3.0.7","v3.0.5","v3.0.4","v3.0.2","v3.0.3","v3.0.0","v3.0.1","v3.0.0-rc.4","v3.0.0-rc.3","v3.0.0-rc.2","v3.0.0-rc.1","3.0.0-rc.1","v3.0.0-beta.7","v3.0.0-beta.6","v3.0.0-beta.5","v3.0.0-beta.4","v3.0.0-beta.3","v3.0.0-beta.2","v3.0.0-beta.1","v3.0.0-alpha.7","v3.0.0-alpha.6","v3.0.0-alpha.4","v3.0.0-alpha.3","v3.0.0-alpha.2","v3.0.0-alpha.1","v2.4-beta-4","v2.4-beta-3","v2.4-beta-2","v2.4-beta-1","v2.4-alpha-1","v2.3.1","v2.3.0","v2.3-rc-2","v2.3-rc-1","v2.3-beta-5","v2.3-beta-4","v2.3-beta-3","v2.3-beta-2","v2.3-beta-1","v2.3-alpha-8","v2.3-alpha-7","v2.3-alpha-6","v2.3-alpha-5","v2.3-alpha-4","v2.3-alpha-3","v2.3-alpha-2","v2.3-alpha-1","2.2-rc-3","2.2-rc-2","2.2-rc-1","2.2-beta-23","2.2-beta-22","2.2-beta-21","2.2-beta-20","2.2-beta-19","2.2-beta-18","2.2-beta-17","2.2-beta-16","2.2-beta-15","2.2-beta-14","2.2-beta-12","2.2-beta-11","2.2-beta-10","2.2-beta-9","2.2-beta-8","2.2-beta-7","2.2-beta-6","2.2-beta-5","2.2-beta-4","2.2-beta-3","2.2-beta-2","dcs-2-a","v0.9.0-beta","v0.8","v0.8rc2","v0.8b4.0","v0.8b4"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-46355.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N"}]}