Memory leak in Cisco Unified Communications Manager IM and Presence Service before 8.6(5)SU1 and 9.x before 9.1(2), and Cisco Unified Presence, allows remote attackers to cause a denial of service (memory and CPU consumption) by making many TCP connections to port (1) 5060 or (2) 5061, aka Bug ID CSCud84959.
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130821-cup