The improper neutralization of special elements in the CGI program 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-2023-41780

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.8%; EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits: 0; none known

The improper neutralization of special elements in the CGI program of the Zyxel NAS326 firmware version V5.21(AAZF.14)C0 and NAS542 firmware version V5.21(ABAG.11)C0 could allow an authenticated attacker to execute some operating system (OS) commands by sending a crafted URL to a vulnerable device.

Patch / fix

links 1

zyxel.com/global/en/support/security-advisories/zyxel-security-advis… advisory

Exploit prediction

1.75% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Zyxel NAS326 firmware
Zyxel NAS542 firmware

Classification

Weakness

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

References

Sources

CVE List CVE-2023-37927
NVD CVE-2023-37927

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.

Summary