CVE-2025-3446: Mattermost Server

Medium severity, CVSS 4.3. EPSS: 0.2% chance of exploitation in the next 30 days.

Mattermost versions 10.6.x <= 10.6.1, 10.5.x <= 10.5.2, 10.4.x <= 10.4.4, 9.11.x <= 9.11.11 fail to check the correct permissions which allows authenticated users who only have permission to invite non-guest users to a team to add guest users to that team via the API to add a single user to a team.

Affected products

• Mattermost Mattermost Server: from 9.11.0, before 9.11.12 (fixed in 9.11.12); from 10.4.0, before 10.4.5 (fixed in 10.4.5); from 10.5.0, before 10.5.3 (fixed in 10.5.3); from 10.6.0, before 10.6.2 (fixed in 10.6.2)

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