Nico Heitmann

BigBlueButton is a virtual classroom platform. When a user joins a session with the microphone initially muted, the client may send audio data to the server despite the mute state. While the server discards this audio, preventing it from being audible to other participants, a malicious server operator could potentially access this data. This behavior occurs only between joining the meeting and the first time the user unmutes.

The moderators-only webcams lock setting in BigBlueButton is not enforced on the backend. This allows an attacker to subscribe to viewers' webcams, even when the lock setting is applied, by exploiting the fact that the required `streamId` is sent to all users, regardless of the lock setting.

The issue concerns ineffective user bans in BigBlueButton, an open source web conferencing system. An attacker could register multiple users and join a meeting with one of them. If that user is banned, they could still join the meeting with the remaining registered users from the same extId. This is resolved by improving permissions so that banning a user removes all related users, including those who have not joined the meeting.

The issue affects meetings with polls in BigBlueButton, an open source web conferencing system, where an attacker who is a meeting participant can gain access to sensitive information. Specifically, subscribing to the current-poll collection does not update the client UI but gives the attacker access to the contents of the collection, including individual poll responses.

The issue affects BigBlueButton, an open source web conferencing system, and allows an attacker who is a meeting presenter to start a subscription for poll results before starting an anonymous poll. This subscription can then be used to see individual responses in the anonymous poll.

BigBlueButton is an open source web conferencing system. The system contains a whiteboard grace period to handle delayed messages, but this period can be exploited by attackers to perform actions in the few seconds after their access is revoked. The attacker must be a meeting participant.

BigBlueButton is an open source web conferencing system. The issue concerns Incorrect Authorization for setting emoji status. A user with moderator rights can use the clear status feature to set any emoji status for other users. However, moderators should only be able to set none as the status of other users.

The issue is related to Insufficient Verification of Data Authenticity, resulting in Denial of Service. An attacker can make a Meteor call to `validateAuthToken` using a victim's `userId`, `meetingId`, and an invalid `authToken`. This forces the victim to leave the conference because the resulting verification failure is also observed and handled by the victim's client. The attacker must be a participant in any meeting on the server.

BigBlueButton is an open source web conferencing system. An attacker can circumvent access controls to obtain the content of public chat messages from different meetings on the server, provided they are a participant in a meeting on the server.

BigBlueButton is an open source web conferencing system. An attacker can circumvent access restrictions for drawing on the whiteboard. The permission check is inadvertently skipped on the server, due to a previously introduced grace period. The attacker must be a meeting participant.

BigBlueButton is an open source web conferencing system. An attacker who is able to obtain the meeting identifier for a meeting on a server can find information related to an external video being shared, like the current timestamp and play/pause. The problem has been patched by modifying the stream to send the data only for users in the meeting.

BigBlueButton is an open source web conferencing system. An attacker, who needs to be a participant in the meeting, could send messages to a locked chat within a 5-second grace period after the lock setting was changed.

BigBlueButton is an open source web conferencing system. An attacker can circumvent access controls to gain access to all breakout rooms of the meeting they are in. The permission checks rely on knowledge of internal ids rather than on verification of the role of the user.