CVE-2023-23621: Discourse

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches. There are no known workarounds.

Affected products

• Discourse Discourse: before 3.0.1 (fixed in 3.0.1); version 1.1.0 only; version 1.2.0 only; version 1.3.0 only; version 1.4.0 only; version 1.5.0 only; …

Published 2023-01-28. Last modified 2026-06-17.