CVE-2023-37927Network attack vector

Authenticated command execution via unneutralized CGI input

Published Nov 30, 2023 · Updated Feb 13, 2025

OS command injection in Zyxel NAS326 and NAS542 firmware allows remote authenticated users to execute commands via a crafted URL. The CGI program fails to neutralize special elements in URL input before incorporating it into an operating system command. Valid device credentials are required; affected builds are NAS326 5.21(AAZF.14)C0 and earlier and NAS542 5.21(ABAG.11)C0 and earlier, and successful injection runs commands on the appliance.

CVSS severity8.8
High
EPSS probability1.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in Zyxel NAS326 and NAS542 firmware allows remote authenticated users to execute commands via a crafted URL. The CGI program fails to neutralize special elements in URL input before incorporating it into an operating system command. Valid device credentials are required; affected builds are NAS326 5.21(AAZF.14)C0 and earlier and NAS542 5.21(ABAG.11)C0 and earlier, and successful injection runs commands on the appliance.

The record

CVE
CVE-2023-37927
Published
Nov 30, 2023
Updated
Feb 13, 2025
Vendor
Zyxel Networks
Product
NAS542 Firmware
Classifications
CWE-78, T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 30, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=V5.21(ABAG.11)C0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zyxel Networks · NAS542 Firmwareversion=V5.21(ABAG.11)C0
Zyxel Networks · NAS326 Firmwareversion=V5.21(AAZF.14)C0

Published CVSS scores

8.8Zyxel CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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