CVE-2025-27111

Overview

Rack is a modular Ruby web server interface. The Rack::Sendfile middleware logs unsanitised header values from the X-Sendfile-Type header, allowing an attacker toinject escape sequences (such as newline characters) into the header, resulting in log injection.

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This vulnerability affects Rack versions prior to 2.2.12, 3.0.13, and 3.1.11.

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Details

Module Info

• ‍Product: Rack‍
• Affected packages: rack‍
• Affected versions: <2.2.12, <3.0.13, <3.1.11‍
• Github repository: https://github.com/rack/rack‍
• Published packages: https://rubygems.org/gems/rack‍
• Package manager: RubyGems‍
• Fixed in: Rack v2.2.12, v3.0.13, v3.1.11

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Vulnerability Info

The vulnerability stems from improper neutralization of escape sequences in log entries, specifically the X-Sendfile-Type header in the Rack::Sendfile middleware. This allows attackers to manipulate log files by injecting newline characters, whichcan obscure attack traces and complicate security audits.

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Steps To Reproduce

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1. Set up a web server using a vulnerable version of Rack.

2. Send an HTTP request with a malicious X-Sendfile-Type header containing newline characters.

3. Observe the manipulation of log entries due to the unsanitized header value.

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Mitigation

• Upgrade to the latest version of Rack 4+.
  
• If unable to upgrade, consider seeking assistance from a commercial support partner like HeroDevs.

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Credit

N/A