CVE-2025-24808 Discourse has race condition when adding users to a group DM
Attackers can bypass user limits in group DMs by exploiting a race condition, allowing unauthorized addition of users beyond the configured maximum.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-24808?
CVE-2025-24808 is a medium-severity vulnerability in Discourse Discourse, published on 26 Mar 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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 `add_users_to_channel` service inside a distributed lock/mutex in order to avoid the race condition.
Weakness: CWE-362
Which versions are affected by CVE-2025-24808?
1 open source package ship an affected version, including discourse. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
discourse Bitnami | All versions | 3.4.0 |
Products include Discourse Discourse.
How do I fix CVE-2025-24808?
Upgrade discourse to 3.4.0 or later.
Is CVE-2025-24808 being exploited?
There is no known exploitation of CVE-2025-24808 in the wild and no public exploit code.
Other vulnerabilities in Discourse Discourse
- CVE-2021-41163 RCE via malicious SNS subscription payload
- CVE-2022-36066 Discourse vulnerable to RCE via admins uploading maliciously zipped file
- CVE-2022-39356 Discourse user account takeover via email and invite link
- CVE-2023-22468 Discourse vulnerable to Cross-site Scripting in local oneboxes
- CVE-2026-27934 Discourse leaks private topic title and post excerpt via user action API endpoint
Sources
Also known as BIT-discourse-2025-24808, GHSA-hfcx-qjw6-573r.