In PHP before 5.6.28 and 7.x before 7.0.13, incorrect handling of various URI components in the URL parser could be used by attackers to bypass hostname-specific URL checks, as demonstrated by evil.example.com:firstname.lastname@example.org/ and evil.example.com:email@example.com/ inputs to the parse_url function (implemented in the php_url_parse_ex function in ext/standard/url.c).
Red Hat Product Security has rated this issue as having Moderate security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.