# CVE-2020-12423: Other in Firefox

> Firefox on Windows may load a malicious DLL from the user's PATH if the system DLL is missing, allowing arbitrary code execution.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/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:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 9 Jul 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-qj63-c77f-88gh

## What is CVE-2020-12423?

CVE-2020-12423 is a high-severity vulnerability in Mozilla Firefox, published on 9 Jul 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

When the Windows DLL "webauthn.dll" was missing from the Operating System, and a malicious one was placed in a folder in the user's %PATH%, Firefox may have loaded the DLL, leading to arbitrary code execution. *Note: This issue only affects the Windows operating system; other operating systems are unaffected.* This vulnerability affects Firefox < 78.

Weakness: CWE-427 (Uncontrolled Search Path Element)

## Which versions are affected by CVE-2020-12423?

It affects 1 product.


Products: Mozilla Firefox.

## How do I fix CVE-2020-12423?

Upgrade to a fixed version.

## Is CVE-2020-12423 being exploited?

There is no known exploitation of CVE-2020-12423 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-2020-12423 and fix it if it is affected.

What it is: CVE-2020-12423 is a high-severity vulnerability in Mozilla Firefox, published on 9 Jul 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-12423 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-2020-12423/ (Markdown: https://insights.sbomify.com/CVE-2020-12423/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-12423
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-12423
- OSV: https://osv.dev/vulnerability/CVE-2020-12423

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-12423/
Summaries are generated and may contain mistakes; the official description above is the record.