The packet driver in Cisco IOS allows remote attackers to cause a denial of service (device reload) via a series of (1) Virtual Switching Systems (VSS) or (2) Bidirectional Forwarding Detection (BFD) packets, aka Bug IDs CSCug41049 and CSCue61890.
http://tools.cisco.com/security/center/content/CiscoSecurityNotice/CVE-2014-2131