The Cisco Express Forwarding processing module in Cisco IOS XE allows remote attackers to cause a denial of service (device reload) via crafted MPLS packets that are not properly handled during IP header validation, aka Bug ID CSCuj23992.
http://www.securitytracker.com/id/1029407
http://www.securityfocus.com/bid/63979
http://tools.cisco.com/security/center/viewAlert.x?alertId=31950
http://tools.cisco.com/security/center/content/CiscoSecurityNotice/CVE-2013-6706