GHSA-mxq2-5jpg-7474MediumCVSS 6.4

Mattermost doesn't validate channel ownership of an existing subscription before applying edits

Published
June 22, 2026
Last Modified
September 15, 2026

🔗 CVE IDs covered (1)

CVE-2026-6062 →

📋 Description

Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT request to the subscription edit endpoint.. Mattermost Advisory ID: MMSA-2026-00650

🎯 Affected products4

  • go/github.com/mattermost/mattermost-server:>= 11.7.0, < 11.7.1
  • go/github.com/mattermost/mattermost-server:>= 11.6.0, < 11.6.3
  • go/github.com/mattermost/mattermost-server:>= 11.5.0, < 11.5.6
  • go/github.com/mattermost/mattermost-server:>= 10.11.0, < 10.11.18

🔗 References (3)