---
title: "CVE-2021-20124: Draytek VigorConnect Path Traversal Vulnerability "
url: https://erroneo.us/security/cve/CVE-2021-20124/
description: "CVE-2021-20124 (DrayTek VigorConnect): Exploited in the wild (CISA KEV). A local file inclusion vulnerability exists in Draytek VigorConnect 1.6.0-B3 in the…"
type: vulnerability-record
section: "Security Digest"
date_published: 2021-10-13
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2021-20124"
kev: true
cvss: 7.5
epss: 0.96308
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2021-20124: Draytek VigorConnect Path Traversal Vulnerability 

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run DrayTek VigorConnect. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-09-03, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-09-24 ; treat that as the outer limit, not the target.
- EPSS 96.3% , percentile 99.9: FIRST’s model estimates a 96.3% chance of exploitation activity in the next 30 days, higher than 99.9% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

## What it is

A local file inclusion vulnerability exists in Draytek VigorConnect 1.6.0-B3 in the file download functionality of the WebServlet endpoint. An unauthenticated attacker could leverage this vulnerability to download arbitrary files from the underlying operating system with root privileges.

## Affected products (CVE record)

- n/a Draytek VigorConnect: 1.6.0-B3

## Severity

- CISA-ADP CVSS 3.1: 7.5 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`

## Exploitation

- CISA KEV: added 2024-09-03; federal due date 2024-09-24. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 96.31% probability of exploitation activity in the next 30 days; percentile 99.9.

## Sources

- [Listed in CISA KEV notes (draytek.com)](https://www.draytek.com/about/security-advisory/vigorconnect-software-security-vulnerability-(cve-2021-20123-cve-2021-20129)
- [CVE.org record CVE-2021-20124](https://www.cve.org/CVERecord?id=CVE-2021-20124)
- [NVD entry CVE-2021-20124](https://nvd.nist.gov/vuln/detail/CVE-2021-20124)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20124)
- [tenable.com](https://www.tenable.com/security/research/tra-2021-42)

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Source page: https://erroneo.us/security/cve/CVE-2021-20124/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt