How severe is CVE-2023-27992?

CVE-2023-27992 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2023-27992 being actively exploited?

Yes. CVE-2023-27992 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2023-06-23, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2023-27992?

CVE-2023-27992 primarily affects Zyxel Nas326 Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-27992?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2023-27992 have an EU (EUVD) identifier?

Yes. CVE-2023-27992 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-31717. It is also flagged as exploited in the EUVD (since 2023-06-23).

When was CVE-2023-27992 published?

CVE-2023-27992 was published on 2023-06-19 and last updated on 2026-06-17.

CVE-2023-27992

CVE-2023-27992 is a critical-severity vulnerability in Zyxel Nas326 Firmware with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2023-06-23). The underlying weakness is classified as CWE-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 84% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2023-06-23)
EU (EUVD) id: EUVD-2023-31717
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2023-06-23)
Weakness: CWE-78
Affected product: Zyxel Nas326 Firmware
Published: 2023-06-19
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2023-27992?: CVE-2023-27992 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2023-27992 being actively exploited?: Yes. CVE-2023-27992 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2023-06-23, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2023-27992?: CVE-2023-27992 primarily affects Zyxel Nas326 Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-27992?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2023-27992 have an EU (EUVD) identifier?: Yes. CVE-2023-27992 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-31717. It is also flagged as exploited in the EUVD (since 2023-06-23).
When was CVE-2023-27992 published?: CVE-2023-27992 was published on 2023-06-19 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:o:zyxel:nas326_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:nas540_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:nas542_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Zyxel Nas326 Firmware

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CVE-2023-4474 — Critical (CVSS 9.8): The improper neutralization of special elements in the WSGI server of the Zyxel NAS326 firmware version…
CVE-2023-4473 — Critical (CVSS 9.8): A command injection vulnerability in the web server of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542…

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