WebKit, as used in Apple iOS before 8.3 and Apple TV before 7.2, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted web site, a different vulnerability than other WebKit CVEs listed in APPLE-SA-2015-04-08-3 and APPLE-SA-2015-04-08-4.
https://support.apple.com/HT204662
https://support.apple.com/HT204661
http://www.securitytracker.com/id/1032050
http://lists.apple.com/archives/security-announce/2015/Apr/msg00003.html
http://lists.apple.com/archives/security-announce/2015/Apr/msg00002.html