# CVE-2021-42279: Chakra Scripting Engine Memory Corruption Vulnerability

> A memory corruption vulnerability in the Chakra scripting engine allows attackers to execute arbitrary code on affected Windows systems.

- **Severity:** Medium 4.2 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P/RL:O/RC:C`)
- **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:** No
- **Published:** 10 Nov 2021
- **Updated:** 19 Aug 2026
- **Also known as:** GHSA-jgrp-6qqq-3284

## What is CVE-2021-42279?

CVE-2021-42279 is a medium-severity memory corruption vulnerability in Microsoft Windows 10, published on 10 Nov 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

Chakra Scripting Engine Memory Corruption Vulnerability

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-42279?

2 open source packages ship an affected version, including Microsoft.ChakraCore. It affects 5 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Microsoft.ChakraCore` | NuGet | All versions to 1.11.24 | None |
| `Microsoft.ChakraCore` | NuGet | All versions to 1.11.24 | None |

Products: Microsoft Windows 10, Microsoft Windows 11, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows Server 2022.

## How do I fix CVE-2021-42279?

No fix has been published for CVE-2021-42279 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-42279 being exploited?

There is no known exploitation of CVE-2021-42279 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Windows 10

- [CVE-2015-2426](https://insights.sbomify.com/CVE-2015-2426/): Microsoft Windows Adobe Type Manager Library Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2015-1769](https://insights.sbomify.com/CVE-2015-1769/): Microsoft Windows Mount Manager Privilege Escalation (medium 6.6, exploited in the wild)
- [CVE-2020-1467](https://insights.sbomify.com/CVE-2020-1467/): Windows Hard Link Elevation of Privilege Vulnerability (critical 10.0)
- [CVE-2021-26424](https://insights.sbomify.com/CVE-2021-26424/): Windows TCP/IP Remote Code Execution Vulnerability (critical 9.9)
- [CVE-2021-28476](https://insights.sbomify.com/CVE-2021-28476/): Windows Hyper-V Remote Code Execution Vulnerability (critical 9.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42279 and fix it if it is affected.

What it is: CVE-2021-42279 is a medium-severity memory corruption vulnerability in Microsoft Windows 10, published on 10 Nov 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-2021-42279 in the wild and no public exploit code.

Affected packages and fixed versions:
- Microsoft.ChakraCore (NuGet): affected all versions up to 1.11.24; no fix listed
- Microsoft.ChakraCore (NuGet): affected all versions up to 1.11.24; no fix listed

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-2021-42279/ (Markdown: https://insights.sbomify.com/CVE-2021-42279/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42279
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42279
- OSV: https://osv.dev/vulnerability/CVE-2021-42279

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42279/
Summaries are generated and may contain mistakes; the official description above is the record.