CVE-2026-33425

Discourse has inferable private group membership or existence via exclude_groups parameter

State: Published
Severity: 6.9 Medium
Published: Mar 20, 2026
Updated: Mar 23, 2026
Reserved: Mar 19, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	6.9 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-203 Observable Discrepancy
CWE-639 Authorization Bypass Through User-Controlled Key
CWE-862 Missing Authorization

Affected Products

Product	Versions
discoursediscourse	>= 2026.1.0-latest, < 2026.1.2Affected >= 2026.2.0-latest, < 2026.2.1Affected = 2026.3.0-latestAffected

References

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

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