CVE-2026-33425: Discourse

Medium severity, CVSS 5.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, unauthenticated users can determine whether a specific user is a member of a private group by observing changes in directory results when using the `exclude_groups` parameter. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. As a workaround, disable public access to the user directory via Admin → Settings → hide user profiles from public.

Affected products

• Discourse Discourse: from 2026.1.0, before 2026.1.2 (fixed in 2026.1.2); from 2026.2.0, before 2026.2.1 (fixed in 2026.2.1); version 2026.3.0 only

Published 2026-03-21. Last modified 2026-06-17.