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Vulnerabilities

Vulnerability · CVE-2023-27992

Zyxel Multiple NAS Devices Command Injection Vulnerability

Published Jun 19, 2023 · catalog updated Jun 16, 2026 · Zyxel Multiple Network-Attached Storage (NAS) Devices

Patch now

CVE-2023-27992 is in the CISA known-exploited catalog, due Jul 14, 2023. Confirm Zyxel Multiple Network-Attached Storage (NAS) Devices against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
82.83%
Remediation
Remediation guidance
Affected products
cpe zyxel/nas326 firmware · cpe zyxel/nas540 firmware · cpe zyxel/nas542 firmware · vendor Zyxel Multiple Network-Attached Storage (NAS) Devices

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe zyxel/nas326 firmwareversion unspecified
  • cpe zyxel/nas540 firmwareversion unspecified
  • cpe zyxel/nas542 firmwareversion unspecified
  • vendor Zyxel Multiple Network-Attached Storage (NAS) Devicesversion unspecified

How to fix CVE-2023-27992

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2023-27992 is in the CISA known-exploited catalog, due Jul 14, 2023. Confirm Zyxel Multiple Network-Attached Storage (NAS) Devices against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply updates per vendor instructions.

What should an analyst verify?

CWE-78: OS Command Injection. EPSS 82.83%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 19, 2023 · Catalog

    Detected

    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.

  2. Jun 23, 2023 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Jul 14, 2023 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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.

Sources

  • CISA KEVConfirmed exploitationCVE-2023-27992

    Multiple Zyxel network-attached storage (NAS) devices contain a pre-authentication command injection vulnerability that could allow an unauthenticated attacker to execute commands remotely via a crafted HTTP request.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2023-27992

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2023-27992

    30-day exploitation probability 82.8%

    first.org
  • NIST NVDVulnerability recordCVE-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 so

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2023-27992

    Multiple Zyxel network-attached storage (NAS) devices contain a pre-authentication command injection vulnerability that could allow an unauthenticated attacker to execute commands remotely via a crafted HTTP request.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.