Low severity · published Aug 21, 2025
CVE-2025-53971
Channel and Team Membership APIs inadvertently allow loss of Member privileges.
3.8
CVSS
0.2%
EPSS
No
On KEV
Description
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 vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 10% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Mattermost · Mattermost
10.5.0 through 10.5.8; 9.11.0 through 9.11.17 · source: vendor
MS
Mattermost Server · Mattermost
9.11.0 before 9.11.18; 10.5.0 before 10.5.9 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-53971
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-53971
Vendor Advisory
https://mattermost.com/security-updates
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