---
id: "CVE-2023-21674"
kind: "vulnerability"
aliases: ["CVE-2023-21674"]
title: "Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability"
severity: "high"
cvss: 8.8
epss: null
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Windows", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "microsoft windows 10 1507", "fixed": ["10.0.10240.19685"], "affected": "< 10.0.10240.19685", "ecosystem": "vendor"}, {"name": "microsoft windows 10 1607", "fixed": ["10.0.14393.5648"], "affected": "< 10.0.14393.5648", "ecosystem": "vendor"}, {"name": "microsoft windows 10 1809", "fixed": ["10.0.17763.3887"], "affected": "< 10.0.17763.3887", "ecosystem": "vendor"}, {"name": "microsoft windows 10 20h2", "fixed": ["10.0.19042.2486"], "affected": "< 10.0.19042.2486", "ecosystem": "vendor"}, {"name": "microsoft windows 10 21h2", "fixed": ["10.0.19044.2486"], "affected": "< 10.0.19044.2486", "ecosystem": "vendor"}, {"name": "microsoft windows 10 22h2", "fixed": ["10.0.19045.2486"], "affected": "< 10.0.19045.2486", "ecosystem": "vendor"}, {"name": "microsoft windows 11 21h2", "fixed": ["10.0.22000.1455"], "affected": "< 10.0.22000.1455", "ecosystem": "vendor"}, {"name": "microsoft windows 11 22h2", "fixed": ["10.0.22621.1105"], "affected": "< 10.0.22621.1105", "ecosystem": "vendor"}, {"name": "microsoft windows rt 8.1", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "microsoft windows server 2012", "fixed": [], "affected": "= r2", "ecosystem": "vendor"}, {"name": "microsoft windows server 2016", "fixed": ["10.0.14393.5648"], "affected": "< 10.0.14393.5648", "ecosystem": "vendor"}, {"name": "microsoft windows server 2019", "fixed": ["10.0.17763.3887"], "affected": "< 10.0.17763.3887", "ecosystem": "vendor"}, {"name": "microsoft windows server 2022", "fixed": ["10.0.20348.1487"], "affected": "< 10.0.20348.1487", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "infrastructure", "windows"]
not_affected_if: ["non-windows"]
published_at: "2023-01-10T00:00:00+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T22:29:04+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-21674", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-21674", "first_seen_at": "2026-10-23T22:29:04+00:00"}]
---

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

Microsoft Windows' Advanced Local Procedure Call (ALPC) component has an unspecified flaw that lets a local user escalate privileges. Exploitation is confirmed in the wild, per CISA's Known Exploited Vulnerabilities catalog.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Microsoft Windows affected ? fixed ?
- vendor:microsoft windows 10 1507 affected < 10.0.10240.19685 fixed 10.0.10240.19685
- vendor:microsoft windows 10 1607 affected < 10.0.14393.5648 fixed 10.0.14393.5648
- vendor:microsoft windows 10 1809 affected < 10.0.17763.3887 fixed 10.0.17763.3887
- vendor:microsoft windows 10 20h2 affected < 10.0.19042.2486 fixed 10.0.19042.2486
- vendor:microsoft windows 10 21h2 affected < 10.0.19044.2486 fixed 10.0.19044.2486
- vendor:microsoft windows 10 22h2 affected < 10.0.19045.2486 fixed 10.0.19045.2486
- vendor:microsoft windows 11 21h2 affected < 10.0.22000.1455 fixed 10.0.22000.1455
- vendor:microsoft windows 11 22h2 affected < 10.0.22621.1105 fixed 10.0.22621.1105
- vendor:microsoft windows rt 8.1 affected ? fixed ?
- vendor:microsoft windows server 2012 affected = r2 fixed ?
- vendor:microsoft windows server 2016 affected < 10.0.14393.5648 fixed 10.0.14393.5648
- vendor:microsoft windows server 2019 affected < 10.0.17763.3887 fixed 10.0.17763.3887
- vendor:microsoft windows server 2022 affected < 10.0.20348.1487 fixed 10.0.20348.1487

## Fix

Apply the Microsoft Windows security update per vendor instructions (CISA required action); the specific KB or build is unknown from these sources.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-21674
- 2026-10-23T22:29:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2023-21674

## From the sources

Microsoft Windows Advanced Local Procedure Call (ALPC) contains an unspecified vulnerability that allows for privilege escalation.

CISA required action: Apply updates per vendor instructions.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_