Cisco IOS XE Crafted MPLS IP Fragmentation Denial of Service Vulnerability

A vulnerability in the Multiprotocol Label Switching (MPLS) IP fragmentation function of Cisco IOS XE could allow an unauthenticated, remote attacker to cause the Cisco Packet Processor to crash.

The vulnerability is due to input validation processing of the crafted MPLS IP packets. An attacker could exploit this vulnerability by injecting specifically crafted MPLS IP packets that are subject to MPLS fragmentation. An exploit could allow the attacker to cause the Cisco Packet Processor process to crash in Cisco IOS XE software.

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

To exploit this vulnerability, it is likely that an attacker would need access to trusted, internal networks to send crafted MPLS IP packets to the targeted device to be processed. This access requirement may reduce the likelihood 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.