A vulnerability in the CAPWAP packet processing of Cisco IOS XE Wireless Controller Software for the Catalyst CW9800 Family (CVE-2026-20086) allows an unauthenticated remote attacker to cause a denial of service by sending a malformed packet, triggering an unexpected device reload. Cisco has released software updates to address this high-severity vulnerability, and there are no available workarounds.
A vulnerability in the processing of Control and Provisioning of Wireless Access Points (CAPWAP) packets of Cisco IOS XE Wireless Controller Software for the Catalyst CW9800 Family 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 a malformed CAPWAP packet. An attacker could exploit this vulnerability by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload unexpectedly, resulting in a DoS condition. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wlc-dos-hnX5KGOm This advisory is part of the March 2026 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2026 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication . <br/>Security Impact Rating: High <br/>CVE: CVE-2026-20086