CVE-2022-0342

CRITICALNuclei

Zyxel usg40_firmware Improper Authentication

Title source: VulnCheck
STIX 2.1 vulnerability

Record summary

CVE-2022-0342 has a selected CVSS score of 9.8 (critical); EIP currently links 1 Nuclei template.

Description

An authentication bypass vulnerability in the CGI program of Zyxel USG/ZyWALL series firmware versions 4.20 through 4.70, USG FLEX series firmware versions 4.50 through 5.20, ATP series firmware versions 4.32 through 5.20, VPN series firmware versions 4.30 through 5.20, and NSG series firmware versions V1.20 through V1.33 Patch 4, which could allow an attacker to bypass the web authentication and obtain administrative access of the device.

Description source: CVE List

Exploitation context

Known exploitation

VulnCheck KEV
Listed · Oct 17, 2025 · VulnCheck
Reported exploitation
Observed · VulnCheck

Available material

Nuclei templates
1

Affected products and versions

6
ProductSourceVersion range

ATP series firmware

Browse Zyxel / ATP series firmware
CVE List4.32 through 5.20affected

NSG series firmware

Browse Zyxel / NSG series firmware
CVE List1.20 through 1.33 Patch 4affected

USG FLEX series firmware

Browse Zyxel / USG FLEX series firmware
CVE List4.50 through 5.20affected

USG/ZyWALL series firmware

Browse Zyxel / USG/ZyWALL series firmware
CVE List4.20 through 4.70affected

VPN series firmware

Browse Zyxel / VPN series firmware
CVE List4.30 through 5.20affected

usg40_firmware

Browse Zyxel / usg40_firmware
VulnCheckVersion data not supplied

Nuclei templates

1
ProjectDiscoveryCRITICALZyxel - Authentication BypassCVSS 9.8

An authentication bypass vulnerability in the CGI program of Zyxel USG/ZyWALL series firmware versions 4.20 through 4.70, USG FLEX series firmware versions 4.50 through 5.20, ATP series firmware versions 4.32 through 5.20, VPN series firmware versions 4.30 through 5.20, and NSG series firmware versions V1.20 through V1.33 Patch 4, which could allow an attacker to bypass the web authentication and obtain administrative access of the device.

Impact

Unauthenticated attackers can bypass web authentication and obtain administrative access to Zyxel devices, potentially gaining complete control over firewalls and network security configurations.

Remediation

Apply security updates provided by Zyxel for affected USG/ZyWALL, USG FLEX, ATP, VPN, and NSG series devices.

WeaknessesCWE-287
AuthorsSleepingBag945, Powerexploit
Template tagscve2022cvezyxelauth-bypassroutervkevvuln
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CPE: cpe:2.3:o:zyxel:usg40_firmware:*:*:*:*:*:*:*:*
FOFA: body="/2FA-access.cgi" && body="zyxel zyxel_style1"
FOFA: body="/2fa-access.cgi" && body="zyxel zyxel_style1"
https://github.com/gobysec/GobyVuls/blob/master/CVE-2022-0342.md https://nvd.nist.gov/vuln/detail/CVE-2022-0342 https://www.zyxel.com/support/Zyxel-security-advisory-for-authentication-bypass-vulnerability-of-firewalls.shtml https://github.com/f1tao/awesome-iot-security-resource https://github.com/murchie85/twitterCyberMonitor

Source: ProjectDiscovery

References

2