Cisco Unified Communications Manager (CUCM) 8.6 before 8.6(2a)su2, 8.6 BE3k before 8.6(4) BE3k, and 9.x before 9.0(1) allows remote attackers to cause a denial of service (CPU consumption and GUI and voice outages) via malformed packets to unused UDP ports, aka Bug ID CSCtx43337.