MEDIUM 4.6 Go

Mattermost doesn't properly validate CSRF tokens

GHSA-rmhw-c3xr-m3xx · CVE-2026-27659 · GO-2026-5629

Published · Modified

Description

Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to properly validate CSRF tokens in the /api/v4/access_control_policies/{policy_id}/activate endpoint, which allows an attacker to trick an admin into changing access control policy active status via a crafted request. Mattermost Advisory ID: MMSA-2026-00578

Ready to move

Start Securing

Free, no credit card | First findings in minutes