Cisco IOS XR Software DHCP Version 6 Process Hang Vulnerability

A vulnerability in the DHCP version 6 (DHCPv6) code of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a hang condition of the DHCPv6 server process that could cause the software to stop processing DHCPv6 requests.

The vulnerability is due to incorrect handling of malformed DHCPv6 packets. An attacker could exploit this vulnerability by sending a malformed DHCPv6 packet to an affected device configured with DHCPv6 server functionality. An exploit could allow the attacker to cause a hang condition of the DHCPv6 server process that could cause the software to stop processing any further DHCPv6 requests.

Cisco has confirmed the vulnerability in a security notice and released software updates.

To exploit this vulnerability, an attacker may need access to trusted, internal networks to send malformed DCHPv6 packets to a targeted device. In addition, the device must be configured with DCHPv6 server functionality. These requirements may reduce the possibility of a successful exploit.

Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.