A vulnerability in the DHCP processing functionality of Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to the improper processing of DHCP messages. An attacker could exploit this vulnerability by sending malicious DHCP messages to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wlc-dhcp-dos-76pCjPxK