{"id":"CVE-2026-46355","aliases":["GHSA-38fw-2gq7-ccgr"],"url":"https://o3.security/vulnerability/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.","published":"2026-08-20T21:34:40.529Z","modified":"2026-08-22T03:58:04.858133829Z","cvss":{"score":7.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/bigbluebutton/bigbluebutton/commit/972b04e474e195cbd708b5b3f0485fe528a1a85b","label":"bigbluebutton/bigbluebutton@972b04e"},"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-22T03:58:04.858133829Z"}}