CVE-2022-20678: Cisco IOS XE

High severity, CVSS 7.5. EPSS: 1% chance of exploitation in the next 30 days.

A vulnerability in the AppNav-XE feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of certain TCP segments. An attacker could exploit this vulnerability by sending a stream of crafted TCP traffic at a high rate through an interface of an affected device. That interface would need to have AppNav interception enabled. A successful exploit could allow the attacker to cause the device to reload.

Affected products

• Cisco IOS XE: version 16.9.6 only; version 16.12.4 only; version 16.12.5 only; version 17.3.3 only

Published 2022-04-15. Last modified 2026-06-17.