CVE-2026-59830
Discourse is an open-source discussion platform. Prior to 2026.7.0, the post action component failed to escape user-controlled display names before interpolating them into an HTML string passed to trustHTML. A user who could choose a crafted display name could persist markup in post action descriptions. Viewing the affected user activity streams could execute attacker-controlled script in another user's browser. This issue is fixed in version 2026.7.0.
- Published Sep 21, 2026
- CVSS 5.4 medium
- 0.3% chance of exploitation in the next 30 days (EPSS)
- A fix is available