NSXMLParser in Foundation in Apple iOS before 8 allows attackers to read arbitrary files via XML data containing an external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue.
http://archives.neohapsis.com/archives/bugtraq/2014-09/0106.html
https://exchange.xforce.ibmcloud.com/vulnerabilities/96077
http://support.apple.com/kb/HT6441