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.