CVE-2026-7521: Mattermost Server

Medium severity, CVSS 5.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Mattermost versions 11.8.x <= 11.8.0, 11.7.x <= 11.7.3, 11.6.x <= 11.6.5, 10.11.x <= 10.11.20 fail to verify file deletion path which allows an admin with SAML system-console write permissions to delete arbitrary files outside the config directory from the server via the remove file endpoint.. Mattermost Advisory ID: MMSA-2026-00666

Affected products

• Mattermost Mattermost Server: from 10.11.0, before 10.11.21 (fixed in 10.11.21); from 11.6.0, before 11.6.6 (fixed in 11.6.6); from 11.7.0, before 11.7.4 (fixed in 11.7.4); from 11.8.0, before 11.8.1 (fixed in 11.8.1)

Published 2026-07-28. Last modified 2026-07-29.