CVE-2026-33425

EUVD-2026-13906

21.03.2026, 00:16

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.

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	5.3 MEDIUM	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Affected Products (NVD)

Vendor	Product	Version
discourse	discourse	2026.1.0 ≤ 𝑥 < 2026.1.2
discourse	discourse	2026.2.0 ≤ 𝑥 < 2026.2.1
discourse	discourse	2026.3.0

𝑥

= Vulnerable software versions

Common Weakness Enumeration

CWE-203 - Observable Discrepancy
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not.

References

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