Cisco IOS before 15.2(2)E1 on Catalyst switches allows remote attackers to obtain potentially sensitive software-version information via a request to the Network Mobility Services Protocol (NMSP) port, aka Bug ID CSCum62591.
http://www.securitytracker.com/id/1035566
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160413-nms