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CVE-2023-27992

Zyxel Multiple NAS Devices Command Injection

9.8 CRITICALActively exploited (CISA KEV)EPSS 82.8%
  1. Published19 Jun 2023
  2. Added to CISA KEV23 Jun 2023
  3. Remediation due14 Jul 2023
Actively exploited (CISA KEV)

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.

Added to KEV: 23 Jun 2023Federal remediation due: 14 Jul 2023

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Zyxel Nas326 Firmware< 5.21\(aazf.14\)c0
Zyxel Nas540 Firmware< 5.21\(aatb.11\)c0
Zyxel Nas542 Firmware< 5.21\(abag.11\)c0

Remediation

Fixed in
Zyxel Nas326 Firmware≥ 5.21\(aazf.14\)c0
Zyxel Nas540 Firmware≥ 5.21\(aatb.11\)c0
Zyxel Nas542 Firmware≥ 5.21\(abag.11\)c0

References

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Frequently asked

Is CVE-2023-27992 being actively exploited?

Yes. CVE-2023-27992 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 23 Jun 2023.

How severe is CVE-2023-27992?

CVE-2023-27992 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 82.8% probability of exploitation.

Which products are affected by CVE-2023-27992?

Affected products include Zyxel Nas326 Firmware, Zyxel Nas540 Firmware, Zyxel Nas542 Firmware.

How do I fix CVE-2023-27992?

Upgrade affected software to a fixed version, for example Zyxel Nas326 Firmware 5.21\(aazf.14\)c0, Zyxel Nas540 Firmware 5.21\(aatb.11\)c0, Zyxel Nas542 Firmware 5.21\(abag.11\)c0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2023-27992 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.