The CTI Manager service in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 4.x before 4.3(2)sr1a, 6.x before 6.1(3), 7.0x before 7.0(2), 7.1x before 7.1(2), and 8.x before 8.0(1) allows remote attackers to cause a denial of service (service failure) via a malformed message, aka Bug ID CSCsu31800.