The global-configuration implementation on Cisco ASR 9000 devices with software 5.1.3 and 5.3.0 improperly closes vty sessions after a commit/end operation, which allows local users to cause a denial of service (tmp/*config file creation, memory consumption, and device hang) via unspecified vectors, aka Bug ID CSCut93842.
http://www.securitytracker.com/id/1033259
http://tools.cisco.com/security/center/viewAlert.x?alertId=39939