CVE-2026-33425 — Discourse has inferable private group membership or existence via exclude_groups parameter

Description (CNA)

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 (CNA)

Vendor / product	Versions
discourse / discourse	affected >= 2026.1.0-latest, < 2026.1.2; affected >= 2026.2.0-latest, < 2026.2.1; affected = 2026.3.0-latest

CWE

CWE-203, CWE-639, CWE-862

References

https://github.com/discourse/discourse/security/advisories/GHSA-r6rh-xvf5-r5f2

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.