CVE-2025-2527: Mattermost Server

Medium severity, CVSS 4.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request.

Affected products

• Mattermost Mattermost Server: from 9.11.0, before 9.11.12 (fixed in 9.11.12); from 10.5.0, before 10.5.3 (fixed in 10.5.3)

Published 2025-05-15. Last modified 2026-06-17.