A vulnerability in the handling of IEEE 802.11w Protected Management Frames (PMFs) of Cisco Catalyst 9800 Series Wireless Controllers that are running Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to terminate a valid user connection to an affected device. The vulnerability exists because the affected software does not properly validate 802.11w disassociation and deauthentication PMFs that it receives. An attacker could exploit this vulnerability by sending a spoofed 802.11w PMF from a valid, authenticated client on a network adjacent to an affected device. A successful exploit could allow the attacker to terminate a single valid user connection to the affected device.