Cisco IOS XE 3.1 through 3.17 and 16.1 through 16.2 allows remote attackers to cause a denial of service (device reload) via crafted ICMP packets that require NAT, aka Bug ID CSCuw85853.
http://www.securitytracker.com/id/1036914
http://www.securityfocus.com/bid/93200
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160928-esp-nat