---
id: CVE-2020-21733
title: >-
  Sagemcom F@ST3686 v1.0 HUN 3.97.0 has XSS via RgDiagnostics.asp, RgDdns.asp,
  RgFirewallEL.asp, RgVpnL2tpPptp.asp.
summary: >-
  Sagemcom F@ST3686 v1.0 HUN 3.97.0 has XSS via RgDiagnostics.asp, RgDdns.asp,
  RgFirewallEL.asp, RgVpnL2tpPptp.asp.
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cwe:
  - CWE-79
vendor: sagemcom
product: f@st_3686_firmware
affected:
  - f@st_3686_firmware = 1.0_hun_3.97.0
published: '2020-09-14'
updated: '2026-07-05'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2020-21733'
references:
  - url: 'http://sagemcomfst3686v10hun3970.com'
    label: cve@mitre.org
  - url: 'https://github.com/Gr3gPr1est/BugReport/blob/master/CVE-2020-21733'
    label: cve@mitre.org
  - url: >-
      https://github.com/Gr3gPr1est/BugReport/blob/master/SAGEM_F%40ST3686_v1.0_HUN_3.97.0_XSS_Vuln..pdf
    label: cve@mitre.org
  - url: 'http://sagemcom.com'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://sagemcomfst3686v10hun3970.com'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/Gr3gPr1est/BugReport/blob/master/CVE-2020-21733'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://github.com/Gr3gPr1est/BugReport/blob/master/SAGEM_F%40ST3686_v1.0_HUN_3.97.0_XSS_Vuln..pdf
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.0073
epssPercentile: 0.52829
ingestedAt: '2026-07-05T02:00:01.314Z'
---

## Overview

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

## Affected

- `f@st_3686_firmware = 1.0_hun_3.97.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.