CVE-2025-48053: Discourse

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Discourse is an open-source discussion platform. Prior to version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch, sending a malicious URL in a PM to a bot user can cause a reduced the availability of a Discourse instance. This issue is patched in version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch. No known workarounds are available.

Affected products

• Discourse Discourse: before 3.4.4 (fixed in 3.4.4); before 3.5.0 (fixed in 3.5.0); version 3.5.0 only

Published 2025-06-09. Last modified 2026-06-17.