CVE-2018-1164: Zyxel P-870h-51 Firmware

Critical severity, CVSS 9.8. EPSS: 4% chance of exploitation in the next 30 days.

This vulnerability allows remote attackers to cause a denial-of-service condition on vulnerable installations of ZyXEL P-870H-51 DSL Router 1.00(AWG.3)D5. Authentication is not required to exploit this vulnerability. The specific flaw exists within numerous exposed CGI endpoints. The vulnerability is caused by improper access controls that allow access to critical functions without authentication. An attacker can use this vulnerability to reboot affected devices, along with other actions. Was ZDI-CAN-4540.

Affected products

• Zyxel P-870h-51 Firmware: version 1.00(awg.3)d5 only

Published 2018-02-21. Last modified 2026-06-17.