Cisco IOS 12.1 through 12.4, when Cisco Unified Communications Manager Express (CME) or Cisco Unified Survivable Remote Site Telephony (SRST) is enabled, allows remote attackers to cause a denial of service (device reload) via a malformed Skinny Client Control Protocol (SCCP) message, aka Bug ID CSCsz48614, the "SCCP Packet Processing Denial of Service Vulnerability."
http://www.cisco.com/en/US/products/products_security_advisory09186a0080b20f33.shtml
http://tools.cisco.com/security/center/viewAlert.x?alertId=20069