Cyber Resilience

CVE-2023-5372

RCE in Zyxel Nas326 Firmware ≤ 5.21\(aazf.16\)c0

Published
30 January 2024
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 7.2
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.28 98th percentile
Risk Priority 68 floored blend · peak EPSS

Summary

CVE-2023-5372 is a high-severity OS Command Injection (CWE-78) vulnerability in Zyxel Nas326 Firmware. Its CVSS base score is 7.2 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

The vulnerability CVE-2023-5372 is a post-authentication command injection issue, tracked under CWE-78, that affects the web management interface of Zyxel NAS326 firmware versions through V5.21(AAZF.15)C0 and NAS542 firmware versions through V5.21(ABAG.12)C0. An authenticated administrator can supply a specially crafted query parameter in a URL request to cause the device to execute arbitrary operating system commands.

An attacker who already possesses valid administrator credentials on an exposed device can leverage this flaw over the network to achieve full control of the underlying operating system, including the ability to read, modify, or delete data and potentially pivot further into the environment. The CVSS 3.1 score of 7.2 reflects the high impact on confidentiality, integrity, and availability when the attack succeeds.

Zyxel’s security advisory published on 30 January 2024 addresses the issue in the affected NAS products and directs administrators to apply the available firmware updates or configuration changes referenced in the advisory to eliminate the command-injection vector. The associated EPSS values remain near 0.10 with negligible movement between the recorded peak and current figures.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

The post-authentication command injection vulnerability in Zyxel NAS326 firmware versions through V5.21(AAZF.15)C0 and NAS542 firmware versions through V5.21(ABAG.12)C0 could allow an authenticated attacker with administrator privileges to execute some operating system (OS) commands by sending a crafted query parameter attached…

more

to the URL of an affected device’s web management interface.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
T1059.003 Windows Command Shell Execution
Adversaries may abuse the Windows command shell for execution.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-29972Same product: Zyxel Nas326
CVE-2024-6342Same product: Zyxel Nas326
CVE-2023-4473Same product: Zyxel Nas326
CVE-2023-37928Same product: Zyxel Nas326
CVE-2023-35138Same product: Zyxel Nas326
CVE-2024-29973Same product: Zyxel Nas326
CVE-2023-37927Same product: Zyxel Nas326
CVE-2023-4474Same product: Zyxel Nas326
CVE-2023-27988Same product: Zyxel Nas326
CVE-2023-27992Same product: Zyxel Nas326

Affected Assets

zyxel
nas326 firmware
≤ 5.21\(aazf.16\)c0
zyxel
nas542 firmware
≤ 5.21\(abag.13\)c0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.2.5
  • V1.2.8
  • V15.2.5

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover missing or incorrect command sanitization during development.

Input validation directly neutralizes or rejects special characters that would otherwise alter OS command structure.

Least privilege reduces the permissions available to any process that could be subverted by injected commands.

Least functionality restricts available OS commands and interpreters, limiting the blast radius of injection.

Secure engineering principles require proper neutralization of untrusted input before command construction.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.

PR.PS-02 partial match
prevents

Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.

References