Cyber Resilience

CVE-2021-4039

CriticalPublic PoCRCE

Published: 01 March 2022

Published
01 March 2022
Modified
21 November 2024
KEV Added
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Patch
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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 0.7170 98.8th percentile
Risk Priority 63 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-4039 is a critical-severity OS Command Injection (CWE-78) vulnerability in Zyxel Nwa1100-Nh Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 1.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

A command injection vulnerability in the web interface of the Zyxel NWA-1100-NH firmware could allow an attacker to execute arbitrary OS commands on the device.

CWE(s)
CWE-78

Related Threats

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

Affected Assets

zyxel
nwa1100-nh firmware
≤ 2.12\(aasi.3\)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.

SC-27 Platform-independent Applications
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.

SI-10 Information Input Validation
addresses: CWE-78

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

References