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

> Unauthenticated attackers can download arbitrary files with root privileges via a local file inclusion vulnerability in the WebServlet endpoint.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Yes, since 3 Sep 2024 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Oct 2021
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-hj9j-3xxg-6259

## What is CVE-2021-20124?

CVE-2021-20124 is a high-severity path traversal vulnerability in Draytek VigorConnect, published on 13 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2021-20124?

It affects 1 product.


Products: Draytek Vigorconnect.

## How do I fix CVE-2021-20124?

No fix has been published for CVE-2021-20124 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 24 Sep 2024.

## Is CVE-2021-20124 being exploited?

Yes. Attackers have exploited CVE-2021-20124 in the wild since at least 3 Sep 2024.

Public exploit code:

- Draytek VigorConnect 6.0-B3 - Local File Inclusion (nuclei): http/cves/2021/CVE-2021-20124.yaml

## Other vulnerabilities in Draytek VigorConnect

- [CVE-2021-20123](https://insights.sbomify.com/CVE-2021-20123/): Draytek VigorConnect Path Traversal Vulnerability (high 7.5, exploited in the wild)
- [CVE-2021-20125](https://insights.sbomify.com/CVE-2021-20125/): File upload in Draytek VigorConnect (critical 9.8)
- [CVE-2021-20126](https://insights.sbomify.com/CVE-2021-20126/): Cross-site request forgery in Draytek VigorConnect (high 8.8)
- [CVE-2021-20127](https://insights.sbomify.com/CVE-2021-20127/): Path traversal in Draytek VigorConnect (high 8.1)
- [CVE-2021-20129](https://insights.sbomify.com/CVE-2021-20129/): Information disclosure in Draytek VigorConnect (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20124 and fix it if it is affected.

What it is: CVE-2021-20124 is a high-severity path traversal vulnerability in Draytek VigorConnect, published on 13 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2021-20124 in the wild since at least 3 Sep 2024.

Affected product: Draytek VigorConnect. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-20124/ (Markdown: https://insights.sbomify.com/CVE-2021-20124/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20124
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20124
- OSV: https://osv.dev/vulnerability/CVE-2021-20124

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20124/
Summaries are generated and may contain mistakes; the official description above is the record.