Impact

In affected URI version, a bypass exists for the fix to CVE-2025-27221 that can expose user credentials.

When using the + operator to combine URIs, sensitive information like passwords from the original URI can be leaked, violating RFC3986 and making applications vulnerable to credential exposure.

The vulnerability affects the uri gem bundled with the following Ruby series:

0.12.4 and earlier (bundled in Ruby 3.2 series) 0.13.2 and earlier (bundled in Ruby 3.3 series) 1.0.3 and earlier (bundled in Ruby 3.4 series)

Patches

Upgrade to 0.12.5, 0.13.3 or 1.0.4

References

https://www.ruby-lang.org/en/news/2025/02/26/security-advisories/ https://hackerone.com/reports/2957667

In the URI gem before 1.0.3 for Ruby, the URI handling methods (URI.join, URI#merge, URI#+) have an inadvertent leakage of authentication credentials because userinfo is retained even after changing the host.