The Cascading Style Sheets (CSS) implementation in Apple iOS before 9.2.1 and Safari before 9.0.3 mishandles the "a:visited button" selector during height processing, which makes it easier for remote attackers to obtain sensitive browser-history information via a crafted web site.
https://support.apple.com/HT205732
https://support.apple.com/HT205730
https://security.gentoo.org/glsa/201706-15
http://www.securitytracker.com/id/1034737
http://www.securityfocus.com/bid/81263
http://www.securityfocus.com/archive/1/537771/100/0/threaded
http://packetstormsecurity.com/files/136227/WebKitGTK-Memory-Corruption-Denial-Of-Service.html
http://lists.apple.com/archives/security-announce/2016/Jan/msg00004.html
http://lists.apple.com/archives/security-announce/2016/Jan/msg00002.html