CVE-2021-34770: Cisco IOS XE

Critical severity, CVSS 9.8. EPSS: 3% chance of exploitation in the next 30 days.

A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, remote attacker to execute arbitrary code with administrative privileges or cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a logic error that occurs during the validation of CAPWAP packets. An attacker could exploit this vulnerability by sending a crafted CAPWAP packet to an affected device. A successful exploit could allow the attacker to execute arbitrary code with administrative privileges or cause the affected device to crash and reload, resulting in a DoS condition.

Affected products

• Cisco IOS XE: affected versions not specified; version 3.15.1xbs only; version 3.15.2xbs only; version 16.6.4s only; version 16.10.1 only; version 16.10.1e only; …

Published 2021-09-23. Last modified 2026-06-17.