# CVE-2023-21674: Microsoft Windows Advanced Local Procedure Call (ALPC) Privilege Escalation

> An attacker can exploit a use-after-free flaw in Windows ALPC to elevate privileges on affected systems.

- **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C`)
- **Exploited in the wild:** Yes, since 10 Jan 2023 (CISA KEV)
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Jan 2023
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-hqxf-h392-6m7w

## What is CVE-2023-21674?

CVE-2023-21674 is a high-severity use after free vulnerability in Microsoft Windows 10 1507, published on 10 Jan 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2023-21674?

It affects 13 products.


Products: Microsoft Windows 10 1507, Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows 10 20h2, Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 21h2, Microsoft Windows 11 22h2, Microsoft Windows Rt 8.1, Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows Server 2022.

## How do I fix CVE-2023-21674?

No fix has been published for CVE-2023-21674 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 31 Jan 2023.

## Is CVE-2023-21674 being exploited?

Yes. Attackers have exploited CVE-2023-21674 in the wild since at least 10 Jan 2023.

Public exploit code:

- https://github.com/hd3s5aa/CVE-2023-21674 (github_poc): https://github.com/hd3s5aa/CVE-2023-21674

## Other vulnerabilities in Microsoft Windows 10 1507

- [CVE-2017-8543](https://insights.sbomify.com/CVE-2017-8543/): Microsoft Windows Search Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2025-33053](https://insights.sbomify.com/CVE-2025-33053/): Microsoft Windows External Control of File Name or Path (high 8.8, exploited in the wild)
- [CVE-2025-33073](https://insights.sbomify.com/CVE-2025-33073/): Microsoft Windows SMB Client Improper Access Control (high 8.8, exploited in the wild)
- [CVE-2024-49039](https://insights.sbomify.com/CVE-2024-49039/): Microsoft Windows Task Scheduler Privilege Escalation (high 8.8, exploited in the wild)
- [CVE-2024-43461](https://insights.sbomify.com/CVE-2024-43461/): Microsoft Windows MSHTML Platform Spoofing (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-21674 and fix it if it is affected.

What it is: CVE-2023-21674 is a high-severity use after free vulnerability in Microsoft Windows 10 1507, published on 10 Jan 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2023-21674 in the wild since at least 10 Jan 2023.

Affected product: Microsoft Windows 10 1507. 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-2023-21674/ (Markdown: https://insights.sbomify.com/CVE-2023-21674/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-21674
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-21674
- OSV: https://osv.dev/vulnerability/CVE-2023-21674

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-21674/
Summaries are generated and may contain mistakes; the official description above is the record.