CVE-2026-10542

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate channel action ownership which allows channel managers to update actions in other channels via the channel action update endpoint.. Mattermost Advisory ID: MMSA-2026-00692

  • Published Sep 14, 2026
  • CVSS 5.0 medium
  • 0.1% chance of exploitation in the next 30 days (EPSS)

Affected software

CVE-2026-10542 at the National Vulnerability Database