CVE-2026-33425CWE-203CWE-639CWE-862

Discourse has inferable private group membership or existence via exclude_groups parameter

Medium · published March 20, 2026

CVSS v4.0
6.9
EPSS
1%
Percentile
54.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
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
EPSS
0.00765 · 54.9th percentile
Weaknesses
CWE-203 · Observable Discrepancy; CWE-639 · Authorization Bypass Through User-Controlled Key; CWE-862 · Missing Authorization
Published
2026-03-20T23:12Z
EPSS history
Timeline
  • 20 MAR 23:12Z
    Discourse has inferable private group membership or existence via exclude_groups parameter
    cvelistv5