CVE-2025-64641: Mattermost Server

Medium severity, CVSS 4.1. EPSS: 0.2% chance of exploitation in the next 30 days.

Mattermost versions 11.1.x <= 11.1.0, 11.0.x <= 11.0.5, 10.12.x <= 10.12.3, 10.11.x <= 10.11.7 fail to verify that post actions invoking /share-issue-publicly were created by the Jira plugin which allowed a malicious Mattermost user to exfiltrate Jira tickets when victim users interacted with affected posts

Affected products

• Mattermost Mattermost Server: from 10.11.0, before 10.11.8 (fixed in 10.11.8); from 10.12.0, before 10.12.4 (fixed in 10.12.4); from 11.0.0, before 11.0.6 (fixed in 11.0.6); from 11.1.0, before 11.1.1 (fixed in 11.1.1)

Published 2025-12-24. Last modified 2026-06-17.