Executive brief
BigBlueButton is an open-source video conferencing platform used for virtual meetings and distance learning. A presenter with knowledge of another meeting's presentation ID could delete presentations from other meetings without authorization, disrupting those sessions. The vulnerability allows cross-meeting presentation sabotage without requiring authentication to the target meeting.
Technical details
The vulnerability is an authorization bypass in the RemovePresentationPubMsgHdlr.scala component that handles presentation deletion via the GraphQL API endpoint (/api/graphql). The root cause is missing meeting ID verification before deleting a presentation—when a presenter submits a presentationId, the system fails to validate that the presentation belongs to their own meeting. An authenticated presenter with knowledge of another meeting's presentation ID can exploit this by submitting it to delete the foreign presentation, even though they are not part of that meeting. The vulnerability was patched in version 3.0.29 by adding meeting ID verification checks in the deletion handler.
Affected products
- BigBlueButton BigBlueButton prior to 3.0.29
Timeline
- 2026-06-12: patched: Version 3.0.29 released with fix
- 2026-08-20: disclosed