The ScanSafe module in Cisco IOS 15.3(3)M allows remote attackers to cause a denial of service (device reload) via HTTPS packets that require tower processing, aka Bug ID CSCum97038.
http://www.securitytracker.com/id/1030244
http://tools.cisco.com/security/center/viewAlert.x?alertId=34234
http://tools.cisco.com/security/center/content/CiscoSecurityNotice/CVE-2014-3263