Cisco NX-OS 4.1 through 7.2 on Nexus 2000, 5000, 5500, 5600, 6000, 7000, 7700, and 9000 devices allows remote attackers to cause a denial of service (device crash) via crafted IPv4 DHCP packets to the (1) DHCPv4 relay agent or (2) smart relay agent, aka Bug IDs CSCuq24603, CSCur93159, CSCus21693, and CSCut76171.