The API in the WebKit Plug-ins component in Apple Safari before 9 does not provide notification of an HTTP Redirection (aka 3xx) status code to a plugin, which allows remote attackers to bypass intended request restrictions via a crafted web site.
https://support.apple.com/HT205265
http://www.securitytracker.com/id/1033688
http://www.securityfocus.com/bid/79707
http://lists.opensuse.org/opensuse-updates/2016-03/msg00054.html
http://lists.apple.com/archives/security-announce/2015/Sep/msg00007.html