Mattermost doesn't validate user channel membership when attaching Mattermost posts as comments to Jira issues in github.com/mattermost/mattermost-server

Open Source Vulnerabilities CVE-2025-13767

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.

Open Source Vulnerabilities GHSA-fmqf-pmcm-8cx9

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.

Open Source Vulnerabilities GO-2025-4259

Mattermost doesn't validate user channel membership when attaching Mattermost posts as comments to Jira issues in github.com/mattermost/mattermost-server. NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions. (If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.) The additional affected modules and versions are: github.com/mattermost/mattermost/server/v8 before v8.0.0-20251121122154-b57c297c6d7.