CVE-2025-27610

Rack::Static can serve files under the specified root: even if urls: are provided, which may expose other files under the specified root: unexpectedly.

Details

The vulnerability occurs because Rack::Static does not properly sanitize user-supplied paths before serving files. Specifically, encoded path traversal sequences are not correctly validated, allowing attackers to access files outside the designated static file directory.

Mitigation

• Update to the latest version of Rack, or
• Remove usage of Rack::Static, or
• Ensure that root: points at a directory path which only contains files which should be accessed publicly.

It is likely that a CDN or similar static file server would also mitigate the issue.

By exploiting this vulnerability, an attacker can gain access to all files under the specified root: directory, provided they are able to determine then path of the file.

CVE-2025-27610 has a CVSS score of 7.5 (High). The vector is network-reachable, no 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 (2.2.13, 3.0.14, 3.1.12); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-27610? CVE-2025-27610 is a high-severity security vulnerability in rack (rubygems), affecting versions < 2.2.13. It is fixed in 2.2.13, 3.0.14, 3.1.12.
2. How severe is CVE-2025-27610? CVE-2025-27610 has a CVSS score of 7.5 (High). 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 rack are affected by CVE-2025-27610? rack (rubygems) versions < 2.2.13 is affected.
4. Is there a fix for CVE-2025-27610? Yes. CVE-2025-27610 is fixed in 2.2.13, 3.0.14, 3.1.12. Upgrade to this version or later.
5. Is CVE-2025-27610 exploitable, and should I be worried? Whether CVE-2025-27610 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-2025-27610 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-2025-27610?
   • Upgrade rack to 2.2.13 or later
   • Upgrade rack to 3.0.14 or later
   • Upgrade rack to 3.1.12 or later