Cisco Security Advisory – A vulnerability in the IP Version 6 (IPv6) packet processing functions of Cisco IOS XR Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to stop processing IPv6 traffic, leading to a denial of service (DoS) condition on the device. The vulnerability is due to insufficient processing logic for crafted IPv6 packets that are sent to an affected device. An attacker could exploit this vulnerability by sending crafted IPv6 Neighbor Discovery packets to an affected device for processing. A successful exploit could allow the attacker to cause the device to stop processing IPv6 traffic, leading to a DoS condition on the device. Cisco will release software updates that address this vulnerability. There are no workarounds that address this vulnerability.