CVE-2025-11730 – Zyxel ATP & USG Series Security Update
“Perimeter firewalls are meant to block attackers — this vulnerability let them slip through.”
CVE-2025-11730 is a critical vulnerability (CVSS 9.8) affecting Zyxel ATP and USG series firewalls. The issue stems from improper input validation within a network-exposed service, allowing an unauthenticated attacker to execute arbitrary commands on affected devices.
An attacker on the internet could exploit this flaw without valid credentials by sending specially crafted requests to the vulnerable service. Successful exploitation could result in full device compromise, unauthorized configuration changes, interception of network traffic, or use of the firewall as a pivot point into internal networks. Because these appliances sit at the network perimeter, compromise can expose the entire organization.
Zyxel has released firmware updates to address this vulnerability in supported ATP and USG models.