WebKit in Apple iOS before 9.3, Safari before 9.1, and tvOS before 9.2 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.
http://lists.apple.com/archives/security-announce/2016/Mar/msg00000.html
http://lists.apple.com/archives/security-announce/2016/Mar/msg00002.html
http://lists.apple.com/archives/security-announce/2016/Mar/msg00005.html
https://support.apple.com/HT206166
https://support.apple.com/HT206169