CVE-2025-53971

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.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

CVE-2025-53971 has a CVSS score of 3.8 (Low). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (10.5.9, 9.11.18, 8.0.0-20250721095846-c602a4a78e1f); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-53971? CVE-2025-53971 is a low-severity incorrect authorization vulnerability in github.com/mattermost/mattermost-server (go), affecting versions >= 10.5.0, <= 10.5.8. It is fixed in 10.5.9, 9.11.18, 8.0.0-20250721095846-c602a4a78e1f. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. How severe is CVE-2025-53971? CVE-2025-53971 has a CVSS score of 3.8 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2025-53971?
   • github.com/mattermost/mattermost-server (go) (versions >= 10.5.0, <= 10.5.8)
   • github.com/mattermost/mattermost/server/v8 (go) (versions < 8.0.0-20250721095846-c602a4a78e1f)
   • github.com/mattermost/mattermost-server/v5 (go) (versions <= 5.39.3)
   • github.com/mattermost/mattermost-server/v6 (go) (versions <= 6.7.2)
4. Is there a fix for CVE-2025-53971? Yes. CVE-2025-53971 is fixed in 10.5.9, 9.11.18, 8.0.0-20250721095846-c602a4a78e1f. Upgrade to this version or later.
5. Is CVE-2025-53971 exploitable, and should I be worried? Whether CVE-2025-53971 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-53971 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-53971?
   • Upgrade github.com/mattermost/mattermost-server to 10.5.9 or later
   • Upgrade github.com/mattermost/mattermost-server to 9.11.18 or later
   • Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20250721095846-c602a4a78e1f or later