Cisco NX-OS 7.0(1)N1(1), 7.0(1)N1(3), and 7.0(4)N1(1) on Nexus 2000 Fabric Extender devices has a blank root password, which allows local users to gain privileges via unspecified vectors, aka Bug ID CSCur22079.
http://www.securitytracker.com/id/1035088
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160223-nx2000