CVE-2026-46351: Bigbluebutton

High severity, CVSS 8.1. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Bigbluebutton Bigbluebutton: before 3.0.21 (fixed in 3.0.21)

Published 2026-07-16. Last modified 2026-07-17.