CVE-2025-24808: Discourse has race condition when adding users to a group DM
Discourse is an open-source discussion platform. Prior to versions 3.3.4 on the stable branch and 3.4.0.beta5 on the beta branch, someone who is about to reach the limit of users in a group DM may send requests to add new users in parallel. The requests might all go through ignoring the limit due to a race condition. The patch in versions 3.3.4 and 3.4.0.beta5 uses the lock step in service to wrap part of the adduserstochannel service inside a distributed lock/mutex in order to avoid the race condition.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-24808?
CVE-2025-24808 has been classified with a severity rating that indicates a potential risk to user group management in Discourse.
How do I fix CVE-2025-24808?
To mitigate CVE-2025-24808, upgrade to Discourse version 3.3.4 or later for the stable branch, or version 3.4.0.beta5 or later for the beta branch.
What does CVE-2025-24808 affect?
CVE-2025-24808 affects Discourse prior to version 3.3.4 on the stable branch and version 3.4.0.beta5 on the beta branch.
What type of vulnerability is CVE-2025-24808?
CVE-2025-24808 is a vulnerability related to user management in group direct messages on the Discourse platform.
What should I do if I can't upgrade to fix CVE-2025-24808?
If you cannot upgrade, consider implementing rate limiting or monitoring user group requests to prevent abuse until an upgrade is possible.