CVE-2022-29234 is a medium-severity vulnerability classified under CWE-285 (Improper Authorization) affecting the open-source web conferencing system BigBlueButton. The flaw exists in versions starting from 2.2 up to but not including 2.3.18, and from 2.4 up to but not including 2.4.1. The vulnerability allows an authenticated participant in a meeting to send messages to a chat that has been locked, bypassing the intended chat lock restrictions. This bypass is possible during a short grace period of approximately 5 seconds immediately after the chat lock setting is changed. During this window, the system fails to enforce the lock properly, allowing unauthorized message posting. The vulnerability requires the attacker to be a participant in the meeting, so it does not allow external unauthenticated attackers to exploit it remotely without joining the session. The issue was addressed in versions 2.3.18 and 2.4.1, which contain patches to close this authorization gap. No known workarounds exist, and no exploits have been reported in the wild to date. This vulnerability could be leveraged to disrupt meeting communication policies or to send unauthorized messages in locked chats, potentially undermining meeting controls and confidentiality during sensitive discussions.

For European organizations, the impact of this vulnerability primarily concerns the integrity and confidentiality of communications during web conferences. Organizations relying on BigBlueButton for internal meetings, educational sessions, or sensitive discussions may face risks of unauthorized message injection during locked chat periods, which could lead to misinformation, disruption, or leakage of sensitive information. Although the vulnerability does not allow full takeover or data exfiltration, it can undermine trust in the conferencing environment and complicate moderation efforts. Sectors such as education, government, and enterprises using BigBlueButton for remote collaboration are particularly at risk. The limited exploitation window and requirement for attacker participation reduce the risk of large-scale automated attacks but do not eliminate insider threat scenarios or targeted misuse. Given the increasing reliance on remote collaboration tools in Europe, this vulnerability could affect operational continuity and confidentiality in regulated environments if not addressed promptly.

European organizations should prioritize upgrading BigBlueButton installations to versions 2.3.18 or 2.4.1 or later, where the vulnerability is patched. Since no workarounds exist, patching is the primary mitigation strategy. Additionally, organizations should implement strict access controls to limit meeting participation to trusted users only, reducing the risk of malicious insiders exploiting the vulnerability. Monitoring and logging chat activity during meetings can help detect unauthorized message attempts. Administrators should also educate users and moderators to be vigilant during chat lock transitions and consider temporarily disabling chat lock changes during critical meetings if upgrading is delayed. Employing network segmentation and secure deployment practices for BigBlueButton servers can further reduce exposure. Finally, organizations should stay informed about updates from the BigBlueButton project and apply security patches promptly to mitigate emerging risks.