CVE-2023-20227: Cisco IOS XE

High severity, CVSS 7.5. EPSS: 0.9% chance of exploitation in the next 30 days.

A vulnerability in the Layer 2 Tunneling Protocol (L2TP) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of certain L2TP packets. An attacker could exploit this vulnerability by sending crafted L2TP packets to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. Note: Only traffic directed to the affected system can be used to exploit this vulnerability.

Affected products

• Cisco IOS XE: version 16.8.1 only; version 16.8.1a only; version 16.8.1b only; version 16.8.1c only; version 16.8.1d only; version 16.8.1e only; …

Published 2023-09-27. Last modified 2026-06-17.