GHSA-7g2v-jj9q-g3rg Possible Log Injection in Rack::CommonLogger

• RubyGems rack: < 2.2.11 → fixed in 2.2.11 • RubyGems rack: >= 3.0, < 3.0.12 → fixed in 3.0.12 • RubyGems rack: >= 3.1, < 3.1.10 → fixed in 3.1.10

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.