GHSA-fmqf-pmcm-8cx9MediumCVSS 4.3

Mattermost doesn't validate user channel membership when attaching Mattermost posts as comments to Jira issues

Published
December 24, 2025
Last Modified
February 27, 2026

🔗 CVE IDs covered (1)

📋 Description

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 fails to validate user channel membership when attaching Mattermost posts as comments to Jira issues, which allows an authenticated attacker with access to the Jira plugin to read post content and attachments from channels they do not have access to.

🎯 Affected products5

  • go/github.com/mattermost/mattermost/server/v8:< 8.0.0-20251121122154-b57c297c6d7
  • go/github.com/mattermost/mattermost-server:>= 10.11.0, < 10.11.8
  • go/github.com/mattermost/mattermost-server:>= 10.12.0, < 10.12.4
  • go/github.com/mattermost/mattermost-server:>= 11.0.0, < 11.0.6
  • go/github.com/mattermost/mattermost-server:>= 11.1.0, < 11.1.1

🔗 References (6)