Auth bypass in Mattermost
CVE-2025-27715
Mattermost versions 9.11.x <= 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel, which team admins to joining private channels via crafted permalink links without explicit consent from them.
Vulnerability class: Broken Access Control
EPSS: 0.002 (10.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:N.
Affected products
- Mattermost — versions 9.11.0, 10.5.0, 9.11.9
- Mattermost Mattermost_server
Weakness classification (CWE)
References
- responsibledisclosure@mattermost.com (Vendor Advisory)
Frequently asked questions
- What is CVE-2025-27715?
- CVE-2025-27715 is a low-severity vulnerability in Mattermost, classified under Incorrect Authorization. CVSS score: 3.3/10. Published 2025-03-21.
- How severe is CVE-2025-27715?
- Low severity. CVSS v3 base score is 3.3 out of 10.