WebKit in Apple Safari before 4.0, iPhone OS 1.0 through 2.2.1, and iPhone OS for iPod touch 1.1 through 2.2.1 does not prevent web sites from loading third-party content into a subframe, which allows remote attackers to bypass the Same Origin Policy and conduct "clickjacking" attacks via a crafted HTML document.
http://www.vupen.com/english/advisories/2011/0212
http://www.vupen.com/english/advisories/2009/1621
http://www.vupen.com/english/advisories/2009/1522
http://www.securityfocus.com/bid/35317
http://www.debian.org/security/2009/dsa-1950
http://support.apple.com/kb/HT3639
http://support.apple.com/kb/HT3613
http://secunia.com/advisories/43068
http://secunia.com/advisories/37746
http://secunia.com/advisories/35379
http://lists.opensuse.org/opensuse-security-announce/2011-01/msg00006.html
http://lists.apple.com/archives/security-announce/2009/jun/msg00002.html
http://lists.apple.com/archives/security-announce/2009/Jun/msg00005.html