CVE-2025-25184: rack CRLF Injection

Vulnerability summary

CVE-2025-25184 is a medium (CVSS 6.5) CRLF Injection vulnerability in rack. EPSS estimates a 1.19% chance of exploitation in the next 30 days, higher than 67.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 12-02-2025
   PublishedVulnerability first disclosed.
2. 03-11-2025
   Last modifiedVulnerability information updated.

Description

Rack provides an interface for developing web applications in Ruby. Prior to versions 2.2.11, 3.0.12, and 3.1.10, 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. 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. Attackers can break log formats or insert fraudulent entries, potentially obscuring real activity or injecting malicious data into log files. Versions 2.2.11, 3.0.12, and 3.1.10 contain a fix.

• CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
• CWE-117Improper Output Neutralization for LogsThe product constructs a log message from external input, but it does not neutralize or incorrectly neutralizes special elements when the message is written to a log file.