Cisco Security Advisory – A vulnerability in the multicast DNS (mDNS) gateway function of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to reload the vulnerable device. The vulnerability is due to improper validation of mDNS packets. An attacker could exploit this vulnerability by sending malformed IP version 4 (IPv4) or IP version 6 (IPv6) packets on UDP port 5353. An exploit could allow the attacker to cause a denial of service (DoS) condition. Cisco has released free software updates that address this vulnerability.