A vulnerability in Locator/ID Separation Protocol (LISP) control message processing in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a vulnerable device to disable Cisco Express Forwarding and eventually drop traffic passing through.
The vulnerability is due to insufficient checking of certain parameters in LISP control messages on the Ingress Tunnel Router (ITR). An attacker could exploit this vulnerability by sending malformed LISP control messages to the ITR. An exploit could allow the attacker to cause a vulnerable device to disable Cisco Express Forwarding and eventually drop traffic passing through.
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 LISP control messages to a targeted device. This access requirement 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.