Mattermost: >> Mattermost Server >> 9.3.0 Security Vulnerabilities
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
Mattermost Plugin MSTeams versions <2.1.0 and Mattermost Server versions 10.5.x <=10.5.1 with the MS Teams plugin enabled fail to perform constant time comparison on a MSTeams plugin webhook secret which allows an attacker to retrieve the webhook secret of the MSTeams plugin via a timing attack during webhook secret comparison.
CVSS Score
5.3
EPSS Score
0.002
Published
2025-04-16
Mattermost Server versions 9.5.x before 9.5.2, 9.4.x before 9.4.4, 9.3.x before 9.3.3, 8.1.x before 8.1.11 don't limit the number of user preferences which allows an attacker to send a large number of user preferences potentially causing denial of service.
CVSS Score
4.3
EPSS Score
0.001
Published
2024-04-05
Improper Access Control in Mattermost Server versions 9.5.x before 9.5.2, 9.4.x before 9.4.4, 9.3.x before 9.3.3, 8.1.x before 8.1.11 lacked proper access control in the `/api/v4/users/me/teams` endpoint allowing a team admin to get the invite ID of their team, thus allowing them to invite users, even if the "Add Members" permission was explicitly removed from team admins.
CVSS Score
4.7
EPSS Score
0.001
Published
2024-04-05
Mattermost versions 8.1.x before 8.1.11, 9.3.x before 9.3.3, 9.4.x before 9.4.4, and 9.5.x before 9.5.2 fail to authenticate the source of certain types of post actions, allowing an authenticated attacker to create posts as other users via a crafted post action.
CVSS Score
6.5
EPSS Score
0.001
Published
2024-04-05
Mattermost versions 8.1.x before 8.1.10, 9.2.x before 9.2.6, 9.3.x before 9.3.2, and 9.4.x before 9.4.3 fail to limit the number of @-mentions processed per message, allowing an authenticated attacker to crash the client applications of other users via large, crafted messages.
CVSS Score
4.3
EPSS Score
0.001
Published
2024-03-15
Mattermost versions 8.1.x before 8.1.10, 9.2.x before 9.2.6, 9.3.x before 9.3.2, and 9.4.x before 9.4.3 fail to correctly verify account ownership when switching from email to SAML authentication, allowing an authenticated attacker to take over other user accounts via a crafted switch request under specific conditions.
CVSS Score
8.8
EPSS Score
0.003
Published
2024-03-15
Mattermost Jira plugin versions shipped with Mattermost versions 8.1.x before 8.1.10, 9.2.x before 9.2.6, 9.3.x before 9.3.2, and 9.4.x before 9.4.3 fail to escape user-controlled outputs when generating HTML pages, which allows an attacker to perform reflected cross-site scripting attacks against the users of the Mattermost server.
CVSS Score
6.1
EPSS Score
0.004
Published
2024-03-15
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