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Fencer Vulns
critical 9.8

CVE-2023-4474 in the critical feed json

The improper neutralization of special elements in the WSGI server of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542 firmwar…

published 2023-11-30 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-54329

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
29.7%
EPSS 29.7% chance of exploitation in 30 days, percentile 98%
public exploits
0
none known

Summary

The improper neutralization of special elements in the WSGI 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.

Patch / fix

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
2 y ago

Exploit prediction

29.74% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Zyxel NAS326 firmware
  • Zyxel NAS542 firmware
  • zyxel nas326_firmware
  • zyxel nas542_firmware

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.