# CVE-2020-16021: Race condition in Chrome

> A race condition in ChromeOS image burner allows remote attackers with compromised browser processes to achieve OS-level privilege escalation.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/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:** 8 Jan 2021
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-16021, GHSA-q9gg-5799-8666, UBUNTU-CVE-2020-16021

## What is CVE-2020-16021?

CVE-2020-16021 is a high-severity vulnerability in Google Chrome, published on 8 Jan 2021. 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

Race in image burner in Google Chrome on ChromeOS prior to 87.0.4280.66 allowed a remote attacker who had compromised the browser process to perform OS-level privilege escalation via a malicious file.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2020-16021?

It affects 1 product.


Products: Google Chrome.

## How do I fix CVE-2020-16021?

Upgrade to a fixed version.

## Is CVE-2020-16021 being exploited?

There is no known exploitation of CVE-2020-16021 in the wild and no public exploit code.

## Other vulnerabilities in Google Chrome

- [CVE-2022-4135](https://insights.sbomify.com/CVE-2022-4135/): Google Chromium GPU Heap Buffer Overflow (critical 9.6, exploited in the wild)
- [CVE-2020-16017](https://insights.sbomify.com/CVE-2020-16017/): Google Chrome Use-After-Free (critical 9.6, exploited in the wild)
- [CVE-2020-16010](https://insights.sbomify.com/CVE-2020-16010/): Google Chrome for Android UI Heap Buffer Overflow (critical 9.6, exploited in the wild)
- [CVE-2026-87491](https://insights.sbomify.com/CVE-2026-87491/): Google Chromium V8 Out of Bounds Write (high 8.8, exploited in the wild)
- [CVE-2026-85046](https://insights.sbomify.com/CVE-2026-85046/): Google Chromium V8 Type Confusion (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-16021 and fix it if it is affected.

What it is: CVE-2020-16021 is a high-severity vulnerability in Google Chrome, published on 8 Jan 2021. 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-2020-16021 in the wild and no public exploit code.

Affected product: Google Chrome. 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-2020-16021/ (Markdown: https://insights.sbomify.com/CVE-2020-16021/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-16021
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-16021
- OSV: https://osv.dev/vulnerability/CVE-2020-16021

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-16021/
Summaries are generated and may contain mistakes; the official description above is the record.