Huawei USG9520 V300R001C01, USG9560 V300R001C01, and USG9580 V300R001C01 allow unauthenticated attackers to send abnormal DHCP request packets to the affected products to trigger a DoS condition.
http://www.securityfocus.com/bid/94405
http://www.huawei.com/en/psirt/security-advisories/huawei-sa-20161116-01-firewall-en