CVE-2025-41395: Mattermost Server

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to properly validate the props used by the RetrospectivePost custom post type in the Playbooks plugin, which allows an attacker to create a specially crafted post with maliciously crafted props and cause a denial of service (DoS) of the web app for all users.

Affected products

• Mattermost Mattermost Server: from 9.11.0, before 9.11.11 (fixed in 9.11.11); from 10.4.0, before 10.4.3 (fixed in 10.4.3); from 10.5.0, before 10.5.1 (fixed in 10.5.1)

Published 2025-04-24. Last modified 2026-06-17.