SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

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…

CRITICAL 9.8EPSS 41.3%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 41.3%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.

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.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
41.35% probability · 99th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-78
Affected
zyxel/nas326 firmware · zyxel/nas542 firmware
Source
security@zyxel.com.tw
EPSS trend
0%23%45%3 November 2026: 41.35%3 November 20263 November 2026

EPSS 41.3% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.