CVE-2017-3857 Cisco IOS and IOS XE Software Layer 2 Tunneling Protocol Denial of Service Vulnerability (cisco-sa-20170322-l2tp)

A vulnerability in the Layer 2 Tunneling Protocol (L2TP) parsing function of Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload.
The vulnerability is due to insufficient validation of L2TP packets. An attacker could exploit this vulnerability by sending a crafted L2TP packet to an affected device.

A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service condition.

N/A

Patch:
Following are links for downloading patches to fix the vulnerabilities:

cisco-sa-20170322-l2tp: CISCO IOS