CVE-2025-53971

Channel and Team Membership APIs inadvertently allow loss of Member privileges.

CVSS 3.8 LOWEPSS 0.2%CWE-863

Vexday Risk Score

8Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 3.8EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

21 Aug 2025Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

Affected products

Mattermost · Mattermost

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References

https://mattermost.com/security-updates