CVE-2026-33425: Discourse has inferable private group membership or existence via exclude_groups parameter
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 excludegroups 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 Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-33425?
CVE-2026-33425 has a moderate severity rating due to the exposure of private group membership information.
How do I fix CVE-2026-33425?
To fix CVE-2026-33425, upgrade to Discourse versions 2026.3.0-latest.1, 2026.2.1, or 2026.1.2.
Who is affected by CVE-2026-33425?
Unauthenticated users are affected by CVE-2026-33425 as they can infer private group memberships.
What versions of Discourse are vulnerable to CVE-2026-33425?
Discourse versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 are vulnerable to CVE-2026-33425.
What is the main issue in CVE-2026-33425?
The main issue in CVE-2026-33425 is that the exclude_groups parameter allows unauthenticated users to infer private group memberships.