The Wide Area Application Services (WAAS) Express implementation in Cisco IOS 15.1 through 15.5 allows remote attackers to cause a denial of service (device reload) via a crafted TCP segment, aka Bug ID CSCuq59708.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2016-2446
http://www.securitytracker.com/id/1035380
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160323-l4f