CVE-2023-4473 Command injection in NAS326 firmware

Critical 9.8 Published 30 Nov 2023 Updated 16 Dec 2025

Unauthenticated attackers can execute OS commands on Zyxel NAS devices via crafted URLs, requiring firmware updates to mitigate.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2023-4473?

CVE-2023-4473 is a critical command injection vulnerability in Zyxel NAS326 firmware, published on 30 Nov 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A command injection vulnerability in the web server of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542 firmware version V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands by sending a crafted URL to a vulnerable device.

Weakness: CWE-78

Which versions are affected by CVE-2023-4473?

It affects 2 products.

Products include Zyxel Nas326 Firmware, Zyxel Nas542 Firmware.

How do I fix CVE-2023-4473?

No fix has been published for CVE-2023-4473 yet. Limit exposure of the affected software until one is available.

Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.

Is CVE-2023-4473 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-4473 exists.

Sources

Also known as GHSA-2h5j-5qmh-v4qh.