Cisco Security Advisory – A vulnerability in the DHCP version 6 (DHCPv6) server implementation of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper parsing of malformed DHCPv6 packets. An attacker could exploit this vulnerability by sending malformed DHCPv6 packets to be processed by an affected device. An exploit could allow the attacker to cause a memory leak and eventual reload of an affected device.