CVE-2023-27992

Status: AnalyzedCritical (9.8)⚠ Active exploitation

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.

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Base score: 9.8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 83%
Percentile among all scored CVEs: 100
Score date: 10/5/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

CISA KEV — actively exploited

Added to catalog: 6/23/2023
Remediation due date: 7/14/2023
Known ransomware use: Unknown

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access95 %
Primary impactT1059 Command and Scripting Interpreterexecution95 %

Inyección de comandos preautenticación en servidor NAS accesible remotamente (AV:N, PR:N). CWE-78 y descripción confirman ejecución de comandos OS.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Privileged Account Management Vulnerability Scanning Restrict Web-Based Content Network Segmentation Limit Software Installation Limit Access to Resource Over Network

Affected technologies (3)

Zyxel — Nas326 Firmware Zyxel — Nas540 Firmware Zyxel — Nas542 Firmware

CWEs

CWE-78
CWE-78

References

Raw JSON (NVD)

Show

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