WebKit in Apple iOS before 9.3 and Safari before 9.1 does not properly restrict redirects that specify a TCP port number, which allows remote attackers to bypass intended port restrictions via a crafted web site.
https://support.apple.com/HT206171
https://support.apple.com/HT206166
http://www.securitytracker.com/id/1035353
http://www.securityfocus.com/archive/1/537948/100/0/threaded
http://lists.apple.com/archives/security-announce/2016/Mar/msg00005.html
http://lists.apple.com/archives/security-announce/2016/Mar/msg00000.html