CVE-2025-11730: Zyxel Atp Series Firmware

High severity, CVSS 7.2. EPSS: 1.4% chance of exploitation in the next 30 days.

A post‑authentication command injection vulnerability in the Dynamic DNS (DDNS) configuration CLI command in Zyxel ATP series firmware versions from V5.35 through V5.41, USG FLEX series firmware versions from V5.35 through V5.41, USG FLEX 50(W) series firmware versions from V5.35 through V5.41, and USG20(W)-VPN series firmware versions from V5.35 through V5.41 could allow an authenticated attacker with administrator privileges to execute operating system (OS) commands on an affected device by supplying a specially crafted string as an argument to the CLI command.

Affected products

• Zyxel Atp Series Firmware
• Zyxel USG20W-VPN Series Firmware
• Zyxel Usg Flex 50w Series Firmware
• Zyxel Usg Flex Series Firmware

Published 2026-02-05. Last modified 2026-06-17.