Mattermost: >> Mattermost Server Security Vulnerabilities
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 versions 10.5.x <= 10.5.7, 9.11.x <= 9.11.16 fail to negotiate a new token when accepting the invite which allows a user that intercepts both invite and password to send synchronization payloads to the server that originally created the invite via the REST API.
CVSS Score
2.2
EPSS Score
0.0
Published
2025-07-18
Mattermost versions 10.8.x <= 10.8.1, 10.7.x <= 10.7.3, 10.5.x <= 10.5.7, 9.11.x <= 9.11.16 fail to sanitize input paths of file attachments in the bulk import JSONL file, which allows a system admin to read arbitrary system files via path traversal.
CVSS Score
6.8
EPSS Score
0.001
Published
2025-07-18
Mattermost versions 10.5.x <= 10.5.6, 10.8.x <= 10.8.1, 10.7.x <= 10.7.3, 9.11.x <= 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the PendingPostID of recently created posts.
CVSS Score
6.5
EPSS Score
0.0
Published
2025-07-18
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly enforce channel member management permissions when adding participants to playbook runs. This allows authenticated users with member-level permissions to bypass system admin restrictions and add or remove users to/from private channels via the playbook run participants feature, even when the 'Manage Members' permission has been explicitly removed. This can lead to unauthorized access to sensitive channel content and allow guest users to gain channel management privileges.
CVSS Score
5.4
EPSS Score
0.0
Published
2025-06-30
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly validate channel membership when retrieving playbook run metadata, allowing authenticated users who are playbook members but not channel members to access sensitive information about linked private channels including channel name, display name, and participant count through the run metadata API endpoint.
CVSS Score
4.3
EPSS Score
0.0
Published
2025-06-30
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly enforce channel member management permissions in playbook runs, allowing authenticated users without the 'Manage Channel Members' permission to add or remove users from public and private channels by manipulating playbook run participants when the run is linked to a channel.
CVSS Score
4.3
EPSS Score
0.0
Published
2025-06-20
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly retrieve requestorInfo from playbooks handler for guest users which allows an attacker access to the playbook run.
CVSS Score
4.3
EPSS Score
0.0
Published
2025-06-20
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to sanitize filenames in the archive extractor which allows authenticated users to write files to arbitrary locations on the filesystem via uploading archives with path traversal sequences in filenames, potentially leading to remote code execution. The vulnerability impacts instances where file uploads and document search by content is enabled (FileSettings.EnableFileAttachments = true and FileSettings.ExtractContent = true). These configuration settings are enabled by default.
CVSS Score
9.9
EPSS Score
0.004
Published
2025-06-20
Mattermost versions 10.5.x <= 10.5.4, 9.11.x <= 9.11.13 fail to properly restrict API access to team information, allowing guest users to bypass permissions and view information about public teams they are not members of via a direct API call to /api/v4/teams/{team_id}.
CVSS Score
3.1
EPSS Score
0.0
Published
2025-06-11