Mattermost: >> Mattermost Server >> 10.11.15 Security Vulnerabilities
Mattermost versions 11.5.x <= 11.5.1 fail to validate team-level run_create permission against the target team when creating a playbook run which allows an authenticated team member to create runs in teams where they lack permission via specifying a different team ID in the run creation API request. Mattermost Advisory ID: MMSA-2026-00629
CVSS Score
4.3
EPSS Score
0.0
Published
2026-05-21
Mattermost versions <11.0 fail to properly enforce the "Allow users to view archived channels" setting which allows regular users to access archived channel content and files via the "Open in Channel" functionality from followed threads
CVSS Score
3.1
EPSS Score
0.0
Published
2025-11-14
Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events
CVSS Score
6.5
EPSS Score
0.001
Published
2025-11-14
Mattermost versions <11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the `/api/v4/teams/{team_id}/channels/search_archived` endpoint
CVSS Score
4.3
EPSS Score
0.0
Published
2025-11-14