The call-handling implementation in Cisco Unity Connection 8.5 before 8.5(1)SU7 8.6 before 8.6(2a)SU4 9.x before 9.1(2)SU2 and 10.0 before 10.0(1)SU1 when SIP trunk integration is enabled allows remote attackers to cause a denial of service (port consumption) by improperly terminating SIP sessions aka Bug ID CSCul28089.