NSXMLParser in Foundation in Apple iOS before 8.3 and Apple TV before 7.2 allows remote attackers to read arbitrary files via an external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue.
https://support.apple.com/kb/HT204870
https://support.apple.com/HT204662
https://support.apple.com/HT204661
http://www.securitytracker.com/id/1032050
http://www.securityfocus.com/bid/73983
http://lists.apple.com/archives/security-announce/2015/Apr/msg00003.html
http://lists.apple.com/archives/security-announce/2015/Apr/msg00002.html