Integer signedness error in IOBluetoothFamily in the Bluetooth implementation in Apple OS X before 10.10 allows attackers to execute arbitrary code in a privileged context or cause a denial of service (write to kernel memory) via a crafted app.
http://www.securitytracker.com/id/1031650
http://support.apple.com/HT204244
http://lists.apple.com/archives/security-announce/2015/Jan/msg00003.html