# CVE-2021-23883: Null Pointer Dereference vulnerability in McAfee Endpoint Security (ENS)

> A local administrator can crash Windows via a specific system call in McAfee Endpoint Security due to a null pointer dereference.

- **Severity:** Medium 4.0 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 10 Feb 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-fcrq-5g5m-qh6j

## What is CVE-2021-23883?

CVE-2021-23883 is a medium-severity vulnerability in McAfee LLC Endpoint Security (ENS) for Windows, published on 10 Feb 2021. 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

A Null Pointer Dereference vulnerability in McAfee Endpoint Security (ENS) for Windows prior to 10.7.0 February 2021 Update allows a local administrator to cause Windows to crash via a specific system call which is not handled correctly. This varies by machine and had partial protection prior to this update.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2021-23883?

It affects 1 product.


Products: Mcafee Endpoint Security.

## How do I fix CVE-2021-23883?

No fix has been published for CVE-2021-23883 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-23883 being exploited?

There is no known exploitation of CVE-2021-23883 in the wild and no public exploit code.

## Other vulnerabilities in McAfee LLC Endpoint Security (ENS) for Windows

- [CVE-2020-7319](https://insights.sbomify.com/CVE-2020-7319/): Improper Access Control Vulnerability in ENS for Windows (high 8.8)
- [CVE-2020-7264](https://insights.sbomify.com/CVE-2020-7264/): Privilege Escalation vulnerability through symbolic links in ENS for Windows (high 8.8)
- [CVE-2020-7265](https://insights.sbomify.com/CVE-2020-7265/): Privilege Escalation vulnerability through symbolic links in ENSM (high 8.8)
- [CVE-2019-3582](https://insights.sbomify.com/CVE-2019-3582/): McAfee Endpoint Security updates fix a privilege escalation vulnerability (high 8.6)
- [CVE-2020-7257](https://insights.sbomify.com/CVE-2020-7257/): Privilege Escalation vulnerability through Symbolic links in ENS (high 8.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-23883 and fix it if it is affected.

What it is: CVE-2021-23883 is a medium-severity vulnerability in McAfee LLC Endpoint Security (ENS) for Windows, published on 10 Feb 2021. 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-2021-23883 in the wild and no public exploit code.

Affected product: McAfee LLC Endpoint Security (ENS) for Windows. 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-2021-23883/ (Markdown: https://insights.sbomify.com/CVE-2021-23883/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-23883
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-23883
- OSV: https://osv.dev/vulnerability/CVE-2021-23883

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-23883/
Summaries are generated and may contain mistakes; the official description above is the record.