Vulnerability Intelligence Report
Zyxel Multiple NAS Devices Command Injection Vulnerability
CVE-2023-27992
The pre-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.14)C0, NAS540 firmware versions prior to V5.21(AATB.11)C0, and NAS542 firmware versions prior to V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands remotely by sending a crafted HTTP request.
CISA KEV
SSVC: Active Exploitation
Automatable
CVSS Base Score
9.8
CRITICAL
Exploitability:3.9
Impact Score:5.9
EPSS Probability:84.27%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-78 ↗CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| Zyxel | NAS326 firmware | < V5.21(AAZF.14)C0 (affected) |
| Zyxel | NAS540 firmware | < V5.21(AATB.11)C0 (affected) |
| Zyxel | NAS542 firmware | < V5.21(ABAG.11)C0 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Zyxel Corporation · Vendor · Taiwan |
| Reserved | 2023-03-09T08:44:12 |
| Published | 2023-06-19T11:42:41 |
| Last Updated | 2025-10-21T23:05:45 |
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