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GHSA-7g2v-jj9q-g3rg

Possible Log Injection in Rack::CommonLogger

Source: GitHub Advisory Database (reviewed) Moderate CVE-2025-25184

Packages

EcosystemPackageAffectedFixed in
RubyGems rack < 2.2.11 2.2.11
RubyGems rack >= 3.0, < 3.0.12 3.0.12
RubyGems rack >= 3.1, < 3.1.10 3.1.10

Details

As written in the advisory (Markdown source, shown as plain text).

## Summary `Rack::CommonLogger` can be exploited by crafting input that includes newline characters to manipulate log entries. The supplied proof-of-concept demonstrates injecting malicious content into logs. ## Details When a user provides the authorization credentials via `Rack::Auth::Basic`, if success, the username will be put in `env['REMOTE_USER']` and later be used by `Rack::CommonLogger` for logging purposes. The issue occurs when a server intentionally or unintentionally allows a user creation with the username contain CRLF and white space characters, or the server just want to log every login attempts. If an attacker enters a username with CRLF character, the logger will log the malicious username with CRLF characters into the logfile. ## Impact Attackers can break log formats or insert fraudulent entries, potentially obscuring real activity or injecting malicious data into log files. ## Mitigation - Update to the latest version of Rack.

References

External links from the advisory. They lead to third-party sites.