Cisco IOS XR 5.1 and earlier on Network Convergence System 6000 devices allows remote attackers to cause a denial of service (NPU and card hang or reload) via a malformed MPLS packet, aka Bug ID CSCuq10466.
https://exchange.xforce.ibmcloud.com/vulnerabilities/96068
http://www.securitytracker.com/id/1030878
http://www.securityfocus.com/bid/69960
http://tools.cisco.com/security/center/viewAlert.x?alertId=35776
http://tools.cisco.com/security/center/content/CiscoSecurityNotice/CVE-2014-3379