How severe is CVE-2023-4473?

CVE-2023-4473 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-2023-4473 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 41% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-4473?

CVE-2023-4473 primarily affects Zyxel Nas326 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-4473?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2023-4473 published?

CVE-2023-4473 was published on 2023-11-30 and last updated on 2026-06-17.

CVE-2023-4473

CVE-2023-4473 is a critical-severity vulnerability in Zyxel Nas326 Firmware with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 41% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 41% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Zyxel Nas326 Firmware
Published: 2023-11-30
Last modified: 2026-06-17

Description

A command injection vulnerability in the web server of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542 firmware version V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands by sending a crafted URL to a vulnerable device.

Frequently asked questions

What is CVE-2023-4473?: A command injection vulnerability in the web server of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542 firmware version V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands by sending a crafted URL to a vulnerable device.
How severe is CVE-2023-4473?: CVE-2023-4473 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-2023-4473 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 41% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-4473?: CVE-2023-4473 primarily affects Zyxel Nas326 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-4473?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2023-4473 published?: CVE-2023-4473 was published on 2023-11-30 and last updated on 2026-06-17.

References

Affected products (2)

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

More vulnerabilities in Zyxel Nas326 Firmware

CVE-2024-6342 — Critical (CVSS 9.8): **UNSUPPORTED WHEN ASSIGNED** A command injection vulnerability in the export-cgi program of Zyxel NAS326 firmware…
CVE-2024-29974 — Critical (CVSS 9.8): ** UNSUPPORTED WHEN ASSIGNED ** The remote code execution vulnerability in the CGI program “file_upload-cgi” in…
CVE-2024-29973 — Critical (CVSS 9.8): ** UNSUPPORTED WHEN ASSIGNED ** The command injection vulnerability in the “setCookie” parameter in Zyxel NAS326…
CVE-2024-29972 — Critical (CVSS 9.8): ** UNSUPPORTED WHEN ASSIGNED ** The command injection vulnerability in the CGI program "remote_help-cgi" in Zyxel…
CVE-2023-4474 — Critical (CVSS 9.8): The improper neutralization of special elements in the WSGI server of the Zyxel NAS326 firmware version…
CVE-2023-35138 — Critical (CVSS 9.8): A command injection vulnerability in the “show_zysync_server_contents” function of the Zyxel NAS326 firmware…

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