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. http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-1728