# CVE-2021-20127: Path traversal in Draytek VigorConnect

> Authenticated attackers can delete arbitrary files with root privileges via path traversal in the Html5Servlet endpoint of Draytek VigorConnect.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Oct 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-x2rp-7w26-4883

## What is CVE-2021-20127?

CVE-2021-20127 is a high-severity path traversal vulnerability in Draytek VigorConnect, published on 13 Oct 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

An arbitrary file deletion vulnerability exists in the file delete functionality of the Html5Servlet endpoint of Draytek VigorConnect 1.6.0-B3. This allows an authenticated user to arbitrarily delete files in any location on the target operating system with root privileges.

## Which versions are affected by CVE-2021-20127?

It affects 1 product.


Products: Draytek Vigorconnect.

## How do I fix CVE-2021-20127?

No fix has been published for CVE-2021-20127 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20127 being exploited?

There is no known exploitation of CVE-2021-20127 in the wild and no public exploit code.

## 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-2021-20124](https://insights.sbomify.com/CVE-2021-20124/): 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-2021-20129](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-2021-20127 and fix it if it is affected.

What it is: CVE-2021-20127 is a high-severity path traversal vulnerability in Draytek VigorConnect, published on 13 Oct 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-20127 in the wild and no public exploit code.

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-2021-20127/ (Markdown: https://insights.sbomify.com/CVE-2021-20127/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20127
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20127
- OSV: https://osv.dev/vulnerability/CVE-2021-20127

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20127/
Summaries are generated and may contain mistakes; the official description above is the record.