# CVE-2021-28310: Microsoft Win32k Privilege Escalation

> An attacker can exploit a memory corruption flaw in Win32k to gain elevated privileges on affected Windows systems.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C`)
- **Exploited in the wild:** Yes, since 3 Nov 2021 (CISA KEV)
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Apr 2021
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-8mmc-r5c6-h963

## What is CVE-2021-28310?

CVE-2021-28310 is a high-severity memory corruption vulnerability in Microsoft Windows 10 1809, published on 13 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Win32k Elevation of Privilege Vulnerability

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

## Which versions are affected by CVE-2021-28310?

It affects 9 products.


Products: Microsoft Windows 10 1803, Microsoft Windows 10 1809, Microsoft Windows 10 1909, Microsoft Windows 10 2004, Microsoft Windows 10 20h2, Microsoft Windows Server 1909, Microsoft Windows Server 2004, Microsoft Windows Server 2019, Microsoft Windows Server 20h2.

## How do I fix CVE-2021-28310?

No fix has been published for CVE-2021-28310 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 17 Nov 2021.

## Is CVE-2021-28310 being exploited?

Yes. Attackers have exploited CVE-2021-28310 in the wild since at least 3 Nov 2021.

Public exploit code:

- Malicious Payloads that abuses Win32k Elevation of Privilege Vulnerability (CVE-2021-28310) (github_poc): https://github.com/Rafael-Svechinskaya/IOC_for_CVE-2021-28310

## Other vulnerabilities in Microsoft Windows 10 1809

- [CVE-2021-1732](https://insights.sbomify.com/CVE-2021-1732/): Microsoft Win32k Privilege Escalation (high 7.8, exploited in the wild)
- [CVE-2019-1322](https://insights.sbomify.com/CVE-2019-1322/): Microsoft Windows Privilege Escalation (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-28310 and fix it if it is affected.

What it is: CVE-2021-28310 is a high-severity memory corruption vulnerability in Microsoft Windows 10 1809, published on 13 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2021-28310 in the wild since at least 3 Nov 2021.

Affected product: Microsoft Windows 10 1809. 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-2021-28310/ (Markdown: https://insights.sbomify.com/CVE-2021-28310/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-28310
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-28310
- OSV: https://osv.dev/vulnerability/CVE-2021-28310

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-28310/
Summaries are generated and may contain mistakes; the official description above is the record.