Zyxel security advisory for post-authentication command injection vulnerability in NAS products

CVE: CVE-2023-5372

Zyxel has released patches addressing a post-authentication command injection vulnerability in some NAS versions. Users are advised to install them for optimal protection.

What is the vulnerability?

The post-authentication command injection vulnerability in some Zyxel NAS devices could allow an authenticated attacker with administrator privileges to execute some operating system (OS) commands by sending a crafted query parameter attached to the URL of an affected device’s web management interface.

What versions are vulnerable—and what should you do?

After a thorough investigation, we have identified the products affected* at the time of the issue report and provided the firmware patches outlined in the table below.

Affected model Affected version Patch availability
NAS326 V5.21(AAZF.15)C0 and earlier V5.21(AAZF.16)C0
NAS542 V5.21(ABAG.12)C0 and earlier V5.21(ABAG.13)C0
*Note that both the vulnerable models reached end-of-vulnerability-support on Dec. 31, 2023.
Got a question?

Please contact your local service rep or visit Zyxel’s Community for further information or assistance.


Thanks to Gábor Selján from BugProve for reporting the issue to us.

Revision history

2024-1-30: Initial release.