CVE-2025-13870

Mattermost versions 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to validate the user permission when accessing the files and subscribing to the block in Boards, which allows an authenticated user to access other board files and was able to subscribe to the block from other boards that the user does not have access to

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

CVE-2025-13870 has a CVSS score of 3.1 (Low). The vector is network-reachable, low 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 (8.0.0-20250905150616-ba86dfc5876b, 10.11.5, 10.5.13); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-13870? CVE-2025-13870 is a low-severity missing authentication for critical function vulnerability in github.com/mattermost/mattermost/server/v8 (go), affecting versions < 8.0.0-20250905150616-ba86dfc5876b. It is fixed in 8.0.0-20250905150616-ba86dfc5876b, 10.11.5, 10.5.13. A critical operation is accessible without requiring any authentication.
2. How severe is CVE-2025-13870? CVE-2025-13870 has a CVSS score of 3.1 (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-2025-13870?
   • github.com/mattermost/mattermost/server/v8 (go) (versions < 8.0.0-20250905150616-ba86dfc5876b)
   • github.com/mattermost/mattermost (go) (versions >= 10.11.0, < 10.11.5)
4. Is there a fix for CVE-2025-13870? Yes. CVE-2025-13870 is fixed in 8.0.0-20250905150616-ba86dfc5876b, 10.11.5, 10.5.13. Upgrade to this version or later.
5. Is CVE-2025-13870 exploitable, and should I be worried? Whether CVE-2025-13870 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-2025-13870 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-2025-13870?
   • Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20250905150616-ba86dfc5876b or later
   • Upgrade github.com/mattermost/mattermost to 10.11.5 or later
   • Upgrade github.com/mattermost/mattermost to 10.5.13 or later