# CVE-2020-6799: Command injection in Firefox

> Attackers can execute arbitrary code via command line injection when Firefox is the default handler for specific file types on Windows.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 2 Mar 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-8h3q-5823-cjpv

## What is CVE-2020-6799?

CVE-2020-6799 is a high-severity command injection vulnerability in Mozilla Firefox, published on 2 Mar 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Command line arguments could have been injected during Firefox invocation as a shell handler for certain unsupported file types. This required Firefox to be configured as the default handler for a given file type and for a file downloaded to be opened in a third party application that insufficiently sanitized URL data. In that situation, clicking a link in the third party application could have been used to retrieve and execute files whose location was supplied through command line arguments. Note: This issue only affects Windows operating systems and when Firefox is configured as the default handler for non-default filetypes. Other operating systems are unaffected. This vulnerability affects Firefox < 73 and Firefox < ESR68.5.

Weakness: CWE-88 (Improper Neutralization of Argument Delimiters in a Command)

## Which versions are affected by CVE-2020-6799?

It affects 2 products.


Products: Mozilla Firefox, Mozilla Firefox Esr.

## How do I fix CVE-2020-6799?

Upgrade to a fixed version.

## Is CVE-2020-6799 being exploited?

There is no known exploitation of CVE-2020-6799 in the wild and no public exploit code.

## Other vulnerabilities in Mozilla Firefox

- [CVE-2019-11708](https://insights.sbomify.com/CVE-2019-11708/): Mozilla Firefox and Thunderbird Sandbox Escape (critical 10.0, exploited in the wild)
- [CVE-2010-3765](https://insights.sbomify.com/CVE-2010-3765/): Mozilla Multiple Products Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2022-26486](https://insights.sbomify.com/CVE-2022-26486/): Mozilla Firefox Use-After-Free (critical 9.6, exploited in the wild)
- [CVE-2022-26485](https://insights.sbomify.com/CVE-2022-26485/): Mozilla Firefox Use-After-Free (high 8.8, exploited in the wild)
- [CVE-2019-11707](https://insights.sbomify.com/CVE-2019-11707/): Mozilla Firefox and Thunderbird Type Confusion (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-6799 and fix it if it is affected.

What it is: CVE-2020-6799 is a high-severity command injection vulnerability in Mozilla Firefox, published on 2 Mar 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-6799 in the wild and no public exploit code.

Affected product: Mozilla Firefox. 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-2020-6799/ (Markdown: https://insights.sbomify.com/CVE-2020-6799/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-6799
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-6799
- OSV: https://osv.dev/vulnerability/CVE-2020-6799

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-6799/
Summaries are generated and may contain mistakes; the official description above is the record.