Discourse Stored Cross-Site Scripting Vulnerability in Topic Titles

A stored cross-site scripting vulnerability has been identified in Discourse, an open-source discussion platform. This issue affects versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2. The vulnerability allows for the injection of malicious scripts into topic titles within the solved posts stream. Exploitation of this vulnerability could lead to the execution of harmful scripts in the context of the user viewing the topic.

Impact

Exploitation of this vulnerability could result in stored cross-site scripting, where injected scripts are executed in the context of the user.

Remediation

Users can update to Discourse versions 2026.3.0-latest.1, 2026.2.1, or 2026.1.2, all of which include the necessary patch. As an additional step, ensure that the Content Security Policy is enabled and has not been altered in a way that could increase vulnerability to XSS attacks.