GHSA-v549-xx3c-6pc8MediumCVSS 4.3

Mattermost doesn't check the create_post channel permission during post edit operations

Published
May 18, 2026
Last Modified
June 1, 2026

🔗 CVE IDs covered (1)

CVE-2026-3637 →

📋 Description

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to check the create_post channel permission during post edit operations which allows an authenticated attacker with revoked posting privileges to modify their existing posts via direct API requests to the post update and patch endpoints.. Mattermost Advisory ID: MMSA-2026-00627

🎯 Affected products5

  • go/github.com/mattermost/mattermost/server/v8:>= 10.11.0, < 10.11.14
  • go/github.com/mattermost/mattermost/server/v8:>= 11.4.0, < 11.4.4
  • go/github.com/mattermost/mattermost/server/v8:< 8.0.0-20260316171743-090408f09f53
  • go/github.com/mattermost/mattermost/server/v8:>= 11.5.0, < 11.5.2
  • go/github.com/mattermost/mattermost-server:< 5.3.2-0.20260316171743-090408f09f53

🔗 References (4)