Vulnerability in Discourse

CVE-2025-24808

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.

Vulnerability class: Race Condition

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (10.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 10.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-24808: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

  • Discourse — versions >= 3.4.0.beta1, < 3.4.0.beta5, 3.4.0, < 3.3.4

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-24808?
CVE-2025-24808 is a medium-severity vulnerability in Discourse, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 4.3/10. Published 2025-03-26.
How severe is CVE-2025-24808?
Medium severity. CVSS v3 base score is 4.3 out of 10.