# CVE-2021-4229: ua-parser-js Crypto Mining backdoor

> A malicious backdoor in the ua-parser-js library enables unauthorized cryptocurrency mining and code execution on affected systems.

- **Severity:** Medium 5.0 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L`)
- **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:** 24 May 2022
- **Updated:** 15 Apr 2025
- **Also known as:** GHSA-pjwm-rvh2-c87w

## What is CVE-2021-4229?

CVE-2021-4229 is a medium-severity vulnerability in unspecified ua-parser-js, published on 24 May 2022. 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

A vulnerability was found in ua-parser-js 0.7.29/0.8.0/1.0.0. It has been rated as critical. This issue affects the crypto mining component which introduces a backdoor. Upgrading to version 0.7.30, 0.8.1 and 1.0.1 is able to address this issue. It is recommended to upgrade the affected component.

Weakness: CWE-829 (Inclusion of Functionality from Untrusted Control Sphere), CWE-912 (Hidden Functionality)

## Which versions are affected by CVE-2021-4229?

6 open source packages ship an affected version, including ua-parser-js. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ua-parser-js` | npm | From 0.7.29 | 0.7.30 |
| `ua-parser-js` | npm | From 0.7.29 | 0.7.30 |
| `ua-parser-js` | npm | From 0.8.0 | 0.8.1 |
| `ua-parser-js` | npm | From 0.8.0 | 0.8.1 |
| `ua-parser-js` | npm | From 1.0.0 | 1.0.1 |
| `ua-parser-js` | npm | From 1.0.0 | 1.0.1 |

Products: Ua-Parser-Js Project Ua-Parser-Js.

## How do I fix CVE-2021-4229?

Upgrade ua-parser-js to a fixed version for your release line: 0.7.30, 0.8.1 or 1.0.1.

## Is CVE-2021-4229 being exploited?

There is no known exploitation of CVE-2021-4229 in the wild and no public exploit code.

## Other vulnerabilities in unspecified ua-parser-js

- [CVE-2021-27292](https://insights.sbomify.com/CVE-2021-27292/): Regular Expression Denial of Service (ReDoS) in ua-parser-js (high 7.5)
- [CVE-2026-48125](https://insights.sbomify.com/CVE-2026-48125/): UAParser.js: Unbounded `Sec-CH-UA-Model` parsing can trigger ReDoS in `withClientHints()` (medium 5.3)
- [CVE-2022-25927](https://insights.sbomify.com/CVE-2022-25927/): ReDoS Vulnerability in ua-parser-js version (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-4229 and fix it if it is affected.

What it is: CVE-2021-4229 is a medium-severity vulnerability in unspecified ua-parser-js, published on 24 May 2022. 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-2021-4229 in the wild and no public exploit code.

Affected packages and fixed versions:
- ua-parser-js (npm): affected from 0.7.29; fixed in 0.7.30
- ua-parser-js (npm): affected from 0.7.29; fixed in 0.7.30
- ua-parser-js (npm): affected from 0.8.0; fixed in 0.8.1
- ua-parser-js (npm): affected from 0.8.0; fixed in 0.8.1
- ua-parser-js (npm): affected from 1.0.0; fixed in 1.0.1
- ua-parser-js (npm): affected from 1.0.0; fixed in 1.0.1

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-2021-4229/ (Markdown: https://insights.sbomify.com/CVE-2021-4229/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-4229
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-4229
- OSV: https://osv.dev/vulnerability/CVE-2021-4229

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-4229/
Summaries are generated and may contain mistakes; the official description above is the record.