Cross-site scripting (XSS) vulnerability in WebKit, as used in Apple iOS before 5 and Safari before 5.1.1, allows remote attackers to inject arbitrary web script or HTML via vectors involving inactive DOM windows.
http://lists.apple.com/archives/Security-announce/2011//Oct/msg00001.html
http://lists.apple.com/archives/Security-announce/2011//Oct/msg00004.html
http://support.apple.com/kb/HT4999
http://support.apple.com/kb/HT5000