CVE-2026-84302: Discourse

Medium severity, CVSS 4.2. EPSS: 0.2% chance of exploitation in the next 30 days.

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, Discourse AI reviewables associated with private messages could appear in the moderator review queue of a moderator who was not a participant in the message. Reviewable visibility filtering did not restrict private-message reviewables to the audience permitted to access the underlying private-message topic, allowing the moderator to read otherwise confidential content. Depending on the available reviewable action, the moderator could also modify the private message by closing its topic or deleting a post. Exploitation requires an authenticated moderator account and a pre-existing Discourse AI reviewable associated with a private message. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.

Affected products

• Discourse Discourse: before 2026.7.0 (fixed in 2026.7.0); from 2026.6.0-latest, before 2026.6.1 (fixed in 2026.6.1); from 2026.5.0-latest, before 2026.5.2 (fixed in 2026.5.2); from 2026.1.0-latest, before 2026.1.6 (fixed in 2026.1.6)

Published 2026-09-24. Last modified 2026-09-24.