Auth bypass in Mattermost
CVE-2025-27538
Mattermost versions 10.5.x <= 10.5.1, 9.11.x <= 9.11.9 fail to enforce MFA checks in PUT /api/v4/users/user-id/mfa when the requesting user differs from the target user ID, which allows users with edit_other_users permission to activate or deactivate MFA for other users, even if those users have not set up MFA.
Vulnerability class: Broken Authentication
EPSS: 0.002 (14.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 2.2 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N.
Affected products
- Mattermost — versions 10.5.0, 9.11.0, 10.6.0
- Mattermost Mattermost_server
Weakness classification (CWE)
References
- responsibledisclosure@mattermost.com (Vendor Advisory)
Frequently asked questions
- What is CVE-2025-27538?
- CVE-2025-27538 is a low-severity vulnerability in Mattermost, classified under Missing Authentication for Critical Function. CVSS score: 2.2/10. Published 2025-04-16.
- How severe is CVE-2025-27538?
- Low severity. CVSS v3 base score is 2.2 out of 10.