WebKit, as used in Apple Safari before 5.0.4 and iOS before 4.3, does not properly handle the Attr.style accessor, which allows remote attackers to bypass the Same Origin Policy and inject Cascading Style Sheets (CSS) token sequences via a crafted web site.
lists.apple.com/archives/security-announce/2011//Mar/msg00003.html
lists.apple.com/archives/security-announce/2011//Mar/msg00004.html
support.apple.com/kb/HT4564
support.apple.com/kb/HT4566
www.securityfocus.com/bid/46814
www.securitytracker.com/id?1025182
exchange.xforce.ibmcloud.com/vulnerabilities/66000