CVE-2026-28227: Discourse

Low severity, CVSS 2.7. EPSS: 0.3% chance of exploitation in the next 30 days.

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, TL4 users can publish topics into staff-only categories via the `publish_to_category` topic timer, bypassing authorization checks. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.

Affected products

• Discourse Discourse: before 2025.12.2 (fixed in 2025.12.2); from 2026.1.0, before 2026.1.1 (fixed in 2026.1.1); version 2026.2.0 only

Published 2026-02-26. Last modified 2026-06-17.