BigBlueButton is an open-source virtual classroom. Prior to 3.0.29, BigBlueButton presenters could submit a presentationId through /api/graphql that identified a presentation belonging to another meeting. akka-bbb-apps/src/main/scala/org/bigbluebutton/core/apps/presentationpod/RemovePresentationPubMsgHdlr.scala did not verify the presentation's meeting identifier before deletion, allowing a presenter who knew the identifier to delete another meeting's presentation and disrupt its availability. This issue is fixed in version 3.0.29.
https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-jxpq-r3h3-p75g
https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.29
https://github.com/bigbluebutton/bigbluebutton/commit/c9e93f9af07b9661e286d101b83cbccb891c551f