---
id: "CVE-2024-21338"
kind: "vulnerability"
aliases: ["CVE-2024-21338"]
title: "Windows Kernel Elevation of Privilege Vulnerability"
severity: "high"
cvss: 7.8
epss: null
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Windows", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "microsoft windows 10 1809", "fixed": ["10.0.17763.5458"], "affected": "< 10.0.17763.5458", "ecosystem": "vendor"}, {"name": "microsoft windows 10 21h2", "fixed": ["10.0.19044.4046"], "affected": "< 10.0.19044.4046", "ecosystem": "vendor"}, {"name": "microsoft windows 10 22h2", "fixed": ["10.0.19045.4046"], "affected": "< 10.0.19045.4046", "ecosystem": "vendor"}, {"name": "microsoft windows 11 21h2", "fixed": ["10.0.22000.2777"], "affected": "< 10.0.22000.2777", "ecosystem": "vendor"}, {"name": "microsoft windows 11 22h2", "fixed": ["10.0.22621.3155"], "affected": "< 10.0.22621.3155", "ecosystem": "vendor"}, {"name": "microsoft windows 11 23h2", "fixed": ["10.0.22631.3155"], "affected": "< 10.0.22631.3155", "ecosystem": "vendor"}, {"name": "microsoft windows server 2019", "fixed": ["10.0.17763.5458"], "affected": "< 10.0.17763.5458", "ecosystem": "vendor"}, {"name": "microsoft windows server 2022", "fixed": ["10.0.20348.2322"], "affected": "< 10.0.20348.2322", "ecosystem": "vendor"}, {"name": "microsoft windows server 2022 23h2", "fixed": [], "affected": "<= 10.0.25398.709", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "infrastructure", "multi-user", "ransomware", "self-hosted", "windows"]
not_affected_if: ["patched-windows"]
published_at: "2024-02-13T18:15:49+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T22:29:05+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2024-21338", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-21338", "first_seen_at": "2026-10-23T22:29:05+00:00"}]
---

# Windows Kernel Elevation of Privilege Vulnerability

A flaw in the Windows kernel driver appid.sys exposes an IOCTL handler without proper access control. A local user with any account can use it to escalate to kernel-level (SYSTEM) privileges.

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

## Affected

- vendor:Microsoft Windows affected ? fixed ?
- vendor:microsoft windows 10 1809 affected < 10.0.17763.5458 fixed 10.0.17763.5458
- vendor:microsoft windows 10 21h2 affected < 10.0.19044.4046 fixed 10.0.19044.4046
- vendor:microsoft windows 10 22h2 affected < 10.0.19045.4046 fixed 10.0.19045.4046
- vendor:microsoft windows 11 21h2 affected < 10.0.22000.2777 fixed 10.0.22000.2777
- vendor:microsoft windows 11 22h2 affected < 10.0.22621.3155 fixed 10.0.22621.3155
- vendor:microsoft windows 11 23h2 affected < 10.0.22631.3155 fixed 10.0.22631.3155
- vendor:microsoft windows server 2019 affected < 10.0.17763.5458 fixed 10.0.17763.5458
- vendor:microsoft windows server 2022 affected < 10.0.20348.2322 fixed 10.0.20348.2322
- vendor:microsoft windows server 2022 23h2 affected <= 10.0.25398.709 fixed ?

## Fix

Apply the Microsoft security update for CVE-2024-21338 per vendor instructions; CISA says to discontinue use of the product if mitigations are unavailable.

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2024-21338
- 2026-10-23T22:29:05+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2024-21338

## From the sources

Microsoft Windows Kernel contains an exposed IOCTL with insufficient access control vulnerability within the IOCTL (input and output control) dispatcher in appid.sys that allows a local attacker to achieve privilege escalation.

CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

---

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