The multicast listener discovery (MLD) service on Cisco Wireless LAN Controller (WLC) devices 7.2, 7.3, 7.4 before 7.4.121.0, and 7.5, when MLDv2 Snooping is enabled, allows remote attackers to cause a denial of service (device restart) via a malformed IPv6 MLDv2 packet, aka Bug ID CSCuh74233.