The WebKit Canvas implementation in Apple iOS before 9 allows remote attackers to bypass the Same Origin Policy and obtain sensitive image information via vectors involving a CANVAS element.
http://lists.apple.com/archives/security-announce/2015/Sep/msg00001.html
http://lists.apple.com/archives/security-announce/2015/Sep/msg00007.html
http://lists.opensuse.org/opensuse-updates/2016-03/msg00132.html
http://www.securityfocus.com/bid/76766
http://www.securitytracker.com/id/1033609
http://www.ubuntu.com/usn/USN-2937-1