# CVE-2020-8227: Path traversal in Desktop Client

> A malicious Nextcloud server can force the desktop client to store files outside the sync directory due to missing response sanitization.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 21 Aug 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-8227, GHSA-64gg-6m36-39px, UBUNTU-CVE-2020-8227

## What is CVE-2020-8227?

CVE-2020-8227 is a medium-severity path traversal vulnerability in Desktop Client, published on 21 Aug 2020. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

Missing sanitization of a server response in Nextcloud Desktop Client 2.6.4 for Linux allowed a malicious Nextcloud Server to store files outside of the dedicated sync directory.

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

## Which versions are affected by CVE-2020-8227?

It affects 1 product.


Products: Nextcloud Desktop.

## How do I fix CVE-2020-8227?

Upgrade to a fixed version.

## Is CVE-2020-8227 being exploited?

There is no known exploitation of CVE-2020-8227 in the wild and no public exploit code.

## Other vulnerabilities in Desktop Client

- [CVE-2024-46958](https://insights.sbomify.com/CVE-2024-46958/): Misconfiguration in n/a (critical 9.1)
- [CVE-2020-8224](https://insights.sbomify.com/CVE-2020-8224/): Code injection in Desktop Client (high 7.8)
- [CVE-2020-8225](https://insights.sbomify.com/CVE-2020-8225/): Information disclosure in Desktop Client (high 7.5)
- [CVE-2021-37617](https://insights.sbomify.com/CVE-2021-37617/): Untrusted Search Path in Nextcloud Desktop Client (high 7.3)
- [CVE-2023-28999](https://insights.sbomify.com/CVE-2023-28999/): Nextcloud: Lack of authenticity of metadata keys allows a malicious server to gain access to E2EE folders (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8227 and fix it if it is affected.

What it is: CVE-2020-8227 is a medium-severity path traversal vulnerability in Desktop Client, published on 21 Aug 2020. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-8227 in the wild and no public exploit code.

Affected product: Desktop Client. 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-2020-8227/ (Markdown: https://insights.sbomify.com/CVE-2020-8227/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8227
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8227
- OSV: https://osv.dev/vulnerability/CVE-2020-8227

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8227/
Summaries are generated and may contain mistakes; the official description above is the record.