CVE-2025-27538

Mattermost versions 10.5.x <= 10.5.1, 9.11.x <= 9.11.9 fail to enforce MFA checks in PUT /api/v4/users/user-id/mfa when the requesting user differs from the target user ID, which allows users with edit_other_users permission to activate or deactivate MFA for other users, even if those users have not set up MFA.

A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.

CVE-2025-27538 has a CVSS score of 2.2 (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 (10.5.2, 9.11.10, 8.0.0-20250314142426-c049748b8863); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-27538? CVE-2025-27538 is a low-severity missing authentication for critical function vulnerability in github.com/mattermost/mattermost/server/v8 (go), affecting versions >= 10.5.0, < 10.5.2. It is fixed in 10.5.2, 9.11.10, 8.0.0-20250314142426-c049748b8863. A critical operation is accessible without requiring any authentication.
2. How severe is CVE-2025-27538? CVE-2025-27538 has a CVSS score of 2.2 (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 versions of github.com/mattermost/mattermost/server/v8 are affected by CVE-2025-27538? github.com/mattermost/mattermost/server/v8 (go) versions >= 10.5.0, < 10.5.2 is affected.
4. Is there a fix for CVE-2025-27538? Yes. CVE-2025-27538 is fixed in 10.5.2, 9.11.10, 8.0.0-20250314142426-c049748b8863. Upgrade to this version or later.
5. Is CVE-2025-27538 exploitable, and should I be worried? Whether CVE-2025-27538 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-2025-27538 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-2025-27538?
   • Upgrade github.com/mattermost/mattermost/server/v8 to 10.5.2 or later
   • Upgrade github.com/mattermost/mattermost/server/v8 to 9.11.10 or later
   • Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20250314142426-c049748b8863 or later