Cisco Unified Communications Manager (aka CUCM formerly CallManager) 6.x before 6.1(5) 7.x before 7.1(3b)SU2 and 8.x before 8.0(1) allows remote attackers to cause a denial of service (process failure) via a malformed SIP REG message related to an overflow of the Telephone-URL field aka Bug ID CSCtc62362.