CVE-2026-1628: Mattermost Desktop

Medium severity, CVSS 4.6. EPSS: 0.1% chance of exploitation in the next 30 days.

Mattermost Desktop App versions <=5.13.3 fail to attach listeners restricting navigation to external sites within the Mattermost app which allows a malicious server to expose preload script functionality to untrusted servers via having a user open an external link in their Mattermost server. Mattermost Advisory ID: MMSA-2026-00596

Affected products

• Mattermost Mattermost Desktop: before 5.13.4 (fixed in 5.13.4)

Published 2026-03-02. Last modified 2026-06-17.