CVE-2026-46351
BigBlueButton is an open-source virtual classroom. Prior to 3.0.21, bbb-web generated conference sessionToken values with insufficiently secure randomness in bbb-common-web/src/main/java/org/bigbluebutton/api/Util.java and bigbluebutton-web/grails-app/controllers/org/bigbluebutton/web/controllers/ApiController.groovy, allowing a session user to predict other users' conference session tokens and impersonate them. This issue is fixed in version 3.0.21.
No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.
Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.
Severity metrics
CVSS 3.1 : 8.1 HIGH
Vector: AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.