The Common Flow Table (CFT) feature in Cisco IOS XE 3.6 and 3.7 before 3.7.1S, 3.8 before 3.8.0S, 3.9 before 3.9.0S, 3.10 before 3.10.0S, 3.11 before 3.11.0S, 3.12 before 3.12.0S, 3.13 before 3.13.0S, 3.14 before 3.14.0S, and 3.15 before 3.15.0S, when MMON or NBAR is enabled, allows remote attackers to cause a denial of service (device reload) via malformed IPv6 packets with IPv4 UDP encapsulation, aka Bug ID CSCua79665.
http://www.securitytracker.com/id/1031981
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20150325-iosxe