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Vulnerabilities

Vulnerability · CVE-2022-0342

Zyxel usg40_firmware Improper Authentication

Published Oct 17, 2025 · catalog updated Oct 17, 2025 · Zyxel

Patch now

CVE-2022-0342 is in the CISA known-exploited catalog. Confirm Zyxel against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Unknown—
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
95.13%
Remediation
Remediation guidance
Affected products
vendor Zyxel usg40_firmware

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. VulnCheck canary evidence.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Zyxel usg40_firmwareversion unspecified

How to fix CVE-2022-0342

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2022-0342 is in the CISA known-exploited catalog. Confirm Zyxel against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

No weakness class is stored. EPSS 95.13%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 17, 2025 · VulnCheck KEV

    Detected

    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

  2. Oct 17, 2025 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Sources

  • CVE.orgVulnerability recordCVE-2022-0342

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2022-0342

    30-day exploitation probability 95.1%

    first.org
  • VulnCheck KEVConfirmed exploitationCVE-2022-0342

    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 s

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.