Post-Authentication Command Injection Vulnerability in Zyxel ATP and USG FLEX Series
CVE-2025-11730

7.2HIGH

Key Information:

Vendor

Zyxel
Status
Atp Series Firmware
Usg Flex Series Firmware
Usg Flex 50(w) Series Firmware
Usg20(w)-vpn Series Firmware
Vendor
CVE Published:
5 February 2026

What is CVE-2025-11730?

A post-authentication command injection vulnerability exists in the Dynamic DNS (DDNS) configuration CLI command affecting specific Zyxel firmware versions. This vulnerability allows an attacker with authenticated administrator privileges to execute arbitrary operating system (OS) commands by injecting a malicious string into the CLI command. The vulnerability impacts multiple iterations of the Zyxel ATP and USG FLEX series, emphasizing the need for immediate patching and heightened security measures to protect against potential exploitation.

Affected Version(s)

ATP series firmware versions from V5.35 through V5.41

USG FLEX 50(W) series firmware versions from V5.35 through V5.41

USG FLEX series firmware versions from V5.35 through V5.41

References

https://www.zyxel.com/global/en/support/security-advisori...
vendor-advisory

CVSS V3.1

Score:
7.2
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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