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.