SARA / Free Tools / CVE / CVE-2023-27992

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

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

CVSS

9.8 CRITICAL

EPSS

86.53% (top 0.60%)

CWE

CWE-78

Published

2023-06-19T11:42:41.774Z

Last modified

2025-10-21T23:05:45.675Z

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA KEV — Actively Exploited

Added to KEV

2023-06-23

BOD 22-01 due

2023-07-14

Ransomware use

Unknown

View KEV detail

CVE-2023-27992 on CISA KEV →

01What is this vulnerability?

02Affected products

Vendor	Product	Versions
Zyxel	NAS326 firmware	< V5.21(AAZF.14)C0
Zyxel	NAS540 firmware	< V5.21(AATB.11)C0
Zyxel	NAS542 firmware	< V5.21(ABAG.11)C0

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2023-06-23. Ransomware use: Unknown.

04Recommended remediation

Patch to a fixed version listed in the vendor advisory (see references below).
Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

Published: 2023-06-19T11:42:41.774Z
Last modified: 2025-10-21T23:05:45.675Z
Added to CISA KEV: 2023-06-23
BOD 22-01 due: 2023-07-14

09References

www.zyxel.com — https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advis…

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