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.
https://hackerone.com/reports/2957667
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/uri/CVE-2025-27221.yml