Cyber Resilience

CVE-2023-4473

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 0.3292 97.0th percentile
Risk Priority 39 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2023-4473 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 3.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis

A command injection vulnerability tracked as CVE-2023-4473 affects the web server component in Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542 firmware version V5.21(ABAG.11)C0. The flaw, classified under CWE-78, permits execution of arbitrary operating system commands through specially crafted URLs sent to the device and carries a CVSS 3.1 base score of 9.8.

An unauthenticated attacker with network access can exploit the issue without credentials or user interaction by submitting a malicious URL to the web server. Successful exploitation grants the ability to run OS commands on the affected NAS device, resulting in complete compromise of confidentiality, integrity, and availability.

Zyxel has published a security advisory covering authentication bypass and command injection issues in its NAS products, alongside detailed analysis from BugProve that identifies the affected firmware versions and exploitation vectors. The EPSS score for this CVE stands at 0.3292 with no material change from its recorded peak.

EU & UK References

Vulnerability details

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…

more

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