Cyber Resilience

CVE-2023-4474

CriticalRCE

Published: 30 November 2023

Published
30 November 2023
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.1341 94.4th percentile
Risk Priority 28 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2023-4474 is a critical-severity OS Command Injection (CWE-78) vulnerability in Zyxel Nas326 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 5.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis

CVE-2023-4474 is an OS command injection vulnerability (CWE-78) stemming from improper neutralization of special elements in the WSGI server component. It affects Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542 firmware version V5.21(ABAG.11)C0, carrying a CVSS 3.1 base score of 9.8.

An unauthenticated remote attacker can exploit the flaw by submitting a crafted URL to a vulnerable device, resulting in arbitrary operating-system command execution with full impact on confidentiality, integrity, and availability.

Zyxel has published a security advisory covering authentication-bypass and command-injection issues in its NAS product line, alongside independent analysis from BugProve that details the affected firmware versions and exploitation vectors.

The EPSS score rose from a low baseline to a peak of 0.1628 (current value 0.1341), indicating emerging exploitation interest after public disclosure.

EU & UK References

Vulnerability details

The improper neutralization of special elements in the WSGI 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…

more

a vulnerable device.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

zyxel
nas326 firmware
≤ 5.21\(aazf.14\)c0
zyxel
nas542 firmware
≤ 5.21\(abag.11\)c0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-78

Platform-independent apps typically execute inside a managed runtime or sandbox that restricts direct OS command execution, reducing the ability to exploit OS command injection.

addresses: CWE-78

Validates inputs to block special elements that would alter OS command execution.

References