The SNMP module in Cisco NX-OS 7.0(3)N1(1) and earlier on Nexus 5000 and 6000 devices provides different error messages for invalid requests depending on whether the VLAN ID exists, which allows remote attackers to enumerate VLANs via a series of requests, aka Bug ID CSCup85616.
https://exchange.xforce.ibmcloud.com/vulnerabilities/95329
http://www.securitytracker.com/id/1030746
http://www.securityfocus.com/bid/69266
http://tools.cisco.com/security/center/viewAlert.x?alertId=35338
http://tools.cisco.com/security/center/content/CiscoSecurityNotice/CVE-2014-3341