Cisco NX-OS < 7.0(3)N1(1) - VLAN Enumeration via SNMP Error Message Discrepancy
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.