libxslt, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.
lists.apple.com/archives/security-announce/2016/May/msg00001.html
lists.apple.com/archives/security-announce/2016/May/msg00002.html
lists.apple.com/archives/security-announce/2016/May/msg00003.html
lists.apple.com/archives/security-announce/2016/May/msg00004.html
www.securityfocus.com/bid/90691
www.securitytracker.com/id/1035890
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SK4YNISS22MJY22YX5I6V2U63QZAUEHA/
support.apple.com/HT206564
support.apple.com/HT206566
support.apple.com/HT206567
support.apple.com/HT206568