Mobile Safari in Apple iOS before 7 does not prevent HTML interpretation of a document served with a text/plain content type, which allows remote attackers to conduct cross-site scripting (XSS) attacks by uploading a file.
http://www.securitytracker.com/id/1029054
http://support.apple.com/kb/HT5934
http://secunia.com/advisories/54886
http://lists.apple.com/archives/security-announce/2013/Sep/msg00006.html