CVE-2025-27111: 
Ruby vulnerability analysis and mitigation

CVE-2025-27111 affects Rack, a modular Ruby web server interface. The vulnerability was discovered and disclosed on March 4, 2025, impacting versions < 2.2.12, >= 3.0 and < 3.0.13, and >= 3.1 and < 3.1.11. The issue resides in the Rack::Sendfile middleware which logs unsanitized header values from the X-Sendfile-Type header (GitHub Advisory).

The vulnerability is classified as a log injection flaw (CWE-93, CWE-117) with a CVSS v4.0 Base Score of 6.9 (Medium). The issue occurs when the Rack::Sendfile middleware processes the X-Sendfile-Type header without proper sanitization, allowing attackers to inject escape sequences such as newline characters into the header (NVD, Red Hat).

The vulnerability can lead to log file manipulation, potentially allowing attackers to distort log files, obscure attack traces, and complicate security auditing processes. This can affect the integrity and reliability of system logs (GitHub Advisory).

The vulnerability has been fixed in Rack versions 2.2.12, 3.0.13, and 3.1.11. Organizations are advised to update to these patched versions. As a workaround, if immediate updating is not possible, administrators can remove the usage of Rack::Sendfile (GitHub Advisory).