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 properly handle constant (aka const) declarations in a type-conversion operation during JavaScript exception handling, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) 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/35311
http://support.apple.com/kb/HT3639
http://support.apple.com/kb/HT3613
http://securitytracker.com/id?1022345
http://secunia.com/advisories/43068
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