WebKit, as used in Apple Safari before 6.1.4 and 7.x before 7.0.4, 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-2014-05-21-1.
https://support.apple.com/kb/HT6537
http://www.securityfocus.com/bid/67553
http://support.apple.com/kb/HT6254
http://archives.neohapsis.com/archives/bugtraq/2014-05/0128.html