The HTTP framework on Cisco SPA300, SPA500, and SPA51x devices allows remote attackers to cause a denial of service (device outage) via a series of malformed HTTP requests, aka Bug ID CSCut67385.
http://www.securitytracker.com/id/1036717
http://www.securityfocus.com/bid/92706
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160831-spa