CVE-2025-6465

Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to sanitize file names which allows users with file upload permission to overwrite file attachment thumbnails via path traversal in file streaming APIs.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2025-6465 has a CVSS score of 4.3 (Medium). 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 (10.8.4, 10.5.9, 10.9.4, 10.10.1, 8.0.0-20250708173752-d6b35c41f0ae5); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-6465? CVE-2025-6465 is a medium-severity path traversal vulnerability in github.com/mattermost/mattermost-server (go), affecting versions >= 10.8.0, <= 10.8.3. It is fixed in 10.8.4, 10.5.9, 10.9.4, 10.10.1, 8.0.0-20250708173752-d6b35c41f0ae5. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2025-6465? CVE-2025-6465 has a CVSS score of 4.3 (Medium). 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-2025-6465?
   • github.com/mattermost/mattermost-server (go) (versions >= 10.8.0, <= 10.8.3)
   • github.com/mattermost/mattermost/server/v8 (go) (versions < 8.0.0-20250708173752-d6b35c41f0ae5)
4. Is there a fix for CVE-2025-6465? Yes. CVE-2025-6465 is fixed in 10.8.4, 10.5.9, 10.9.4, 10.10.1, 8.0.0-20250708173752-d6b35c41f0ae5. Upgrade to this version or later.
5. Is CVE-2025-6465 exploitable, and should I be worried? Whether CVE-2025-6465 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-2025-6465 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-2025-6465?
   • Upgrade github.com/mattermost/mattermost-server to 10.8.4 or later
   • Upgrade github.com/mattermost/mattermost-server to 10.5.9 or later
   • Upgrade github.com/mattermost/mattermost-server to 10.9.4 or later
   • Upgrade github.com/mattermost/mattermost-server to 10.10.1 or later
   • Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20250708173752-d6b35c41f0ae5 or later