Apple iOS before 8 enables Bluetooth during all upgrade actions, which makes it easier for remote attackers to bypass intended access restrictions via a Bluetooth session.
http://archives.neohapsis.com/archives/bugtraq/2014-09/0106.html
http://support.apple.com/kb/HT6441
http://www.securityfocus.com/bid/69882
http://www.securityfocus.com/bid/69943