CVE-2026-12284

Mattermost Desktop App versions <=6.2 6.2.2.0 fails to validate the IPC sender in the leaveCall handler which allows a malicious or compromised Mattermost server (or a user with script access to a connected server view) to disconnect an active call belonging to a different connected server via the desktopAPI.leaveCall IPC message. Mattermost Advisory ID: MMSA-2026-00699

  • Published Sep 17, 2026
  • CVSS 3.7 low
  • 0.1% chance of exploitation in the next 30 days (EPSS)

Affected software

CVE-2026-12284 at the National Vulnerability Database