FrankenPHP before 1.13.0 contains a path-split interpretation conflict in splitPos in cgi.go that allows unauthenticated attackers to execute protected PHP scripts by embedding .php inside a filename component. Attackers can request paths like /uploads/a.php.txt/b.php to execute uploads/a.php despite route-level or WAF deny rules and forge PATH_INFO, SCRIPT_NAME, and PHP_SELF values.
CWE-436