The Presence Engine (PE) service in Cisco Unified Presence before 6.0(1) allows remote attackers to cause a denial of service (core dump and service interruption) via malformed packets, aka Bug ID CSCsh50164.
https://exchange.xforce.ibmcloud.com/vulnerabilities/42412
http://www.vupen.com/english/advisories/2008/1534
http://www.securityfocus.com/bid/29219
http://www.cisco.com/en/US/products/products_security_advisory09186a0080995682.shtml