Mattermost: Security Vulnerabilities
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fail to sanitize the team invite ID in the POST /api/v4/teams/:teamId/restore endpoint which allows an team admin with no member invite privileges to get the team’s invite id.
CVSS Score
4.3
EPSS Score
0.0
Published
2025-08-21
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2, 10.10.x <= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system admin to upload non-attachment file types via shared channels that could potentially be placed in arbitrary filesystem directories.
CVSS Score
6.8
EPSS Score
0.001
Published
2025-08-21
Mattermost versions 10.5.x <= 10.5.8 fail to validate access controls at time of access which allows user to read a thread via AI posts
CVSS Score
3.5
EPSS Score
0.0
Published
2025-08-21
Mattermost versions 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate authorization for team scheme role modifications which allows Team Admins to demote Team Members to Guests via the PUT /api/v4/teams/team-id/members/user-id/schemeRoles API endpoint.
CVSS Score
3.8
EPSS Score
0.0
Published
2025-08-21
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fails to sanitize path traversal sequences in template file destination paths, which allows a system admin to perform path traversal attacks via malicious path components, potentially enabling malicious file placement outside intended directories.
CVSS Score
6.8
EPSS Score
0.001
Published
2025-08-21
Mattermost Server versions 10.5.x <= 10.5.9 utilizing the Agents plugin fail to reject empty request bodies which allows users to trick users into clicking malicious links via post actions
CVSS Score
3.5
EPSS Score
0.001
Published
2025-08-21
Mattermost versions 10.9.x <= 10.9.1, 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate file paths during plugin import operations which allows restricted admin users to install unauthorized custom plugins via path traversal in the import functionality, bypassing plugin signature enforcement and marketplace restrictions.
CVSS Score
6.8
EPSS Score
0.001
Published
2025-08-21
Mattermost Confluence Plugin version <1.5.0 fails to handle unexpected request body which allows attackers to crash the plugin via constant hit to server webhook endpoint with an invalid request body.
CVSS Score
5.9
EPSS Score
0.001
Published
2025-08-11
Mattermost Confluence Plugin version <1.5.0 fails to enforce authentication of the user to the Mattermost instance which allows unauthenticated attackers to edit channel subscriptions via API call to the edit channel subscription endpoint.
CVSS Score
7.2
EPSS Score
0.001
Published
2025-08-11
Mattermost Confluence Plugin version <1.5.0 fails to handle unexpected request body which allows attackers to crash the plugin via constant hit to create channel subscription endpoint with an invalid request body.
CVSS Score
7.5
EPSS Score
0.002
Published
2025-08-11