RubySec

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CVE-2025-27111 (rack): Escape Sequence Injection vulnerability in Rack lead to Possible Log Injection

ADVISORIES

GEM

rack

PATCHED VERSIONS

  • ~> 2.2.12
  • ~> 3.0.13
  • >= 3.1.11

DESCRIPTION

Summary

Rack::Sendfile can be exploited by crafting input that includes newline characters to manipulate log entries.

Details

The Rack::Sendfile middleware logs unsanitized header values from the X-Sendfile-Type header. An attacker can exploit this by injecting escape sequences (such as newline characters) into the header, resulting in log injection.

Impact

This vulnerability can distort log files, obscure attack traces, and complicate security auditing.

Mitigation

  • Update to the latest version of Rack, or
  • Remove usage of Rack::Sendfile.

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