CVE-2023-27992: Zyxel Multiple NAS Devices Command Injection Vulnerability

Vulnerability summary

CVE-2023-27992 is a critical (CVSS 9.8) OS Command Injection vulnerability in Zyxel Multiple Network-Attached Storage (NAS) Devices. It is known to be exploited: CISA lists it, first on 23-06-2023. EPSS estimates a 82.83% chance of exploitation in the next 30 days, higher than 99.6% of scored vulnerabilities.

Timeline

1. 19-06-2023
   PublishedVulnerability first disclosed.
2. 23-06-2023
   Added to CISA KEVZyxel Multiple NAS Devices Command Injection Vulnerability
3. 14-07-2023
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

Description

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.

• CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.