The Mobile and Remote Access (MRA) services implementation in Cisco Unified Communications Manager mishandles edge-device identity validation, which allows remote attackers to bypass intended call-reception and call-setup restrictions by spoofing a user, aka Bug ID CSCuu97283.
http://www.securitytracker.com/id/1034377
http://www.securityfocus.com/bid/78741
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151209-ucm