The Sandbox subsystem in Apple iOS before 7 determines the sandboxing requirement for a #! application on the basis of the script interpreter instead of the script, which allows attackers to bypass intended access restrictions via a crafted application.
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