The IDSM-2 drivers in Cisco Intrusion Prevention System (IPS) Software on Cisco Catalyst 6500 devices with an IDSM-2 module allow remote attackers to cause a denial of service (device hang) via malformed IPv4 TCP packets, aka Bug ID CSCuh27460.
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130717-ips