BigBlueButton is an open source web conferencing system. Versions prior to 2.4.3 contain a whiteboard grace period that exists to handle delayed messages, but this grace period could be used by attackers to take actions in the few seconds after their access is revoked. The attacker must be a meeting participant. This issue is patched in version 2.4.3 an version 2.5-alpha-1
CWE-281