CVE-2018-8639
Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA notes
https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2018-8639 ; https://nvd.nist.gov/vuln/detail/CVE-2018-8639
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.
Severity
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation Context
as of October 13, 2026- CISA added CVE-2018-8639 to the KEV catalog 2,273 days after its CVE record was published. The median for entries added in 2025 is 26 days.
- It is one of 390 Microsoft entries in the CISA KEV catalog, and one of 39 added in 2025.
- Its current EPSS score (22.2%) is higher than that of 36% of CISA KEV entries.
Affected Products
| Vendor | Product | Affected versions |
|---|---|---|
| Microsoft | Microsoft Windows 7 | 32-bit Systems Service Pack 1 x64-based Systems Service Pack 1 |
| Microsoft | Microsoft Windows Server 2012 R2 | (Server Core installation) |
| Microsoft | Microsoft Windows RT 8.1 | Windows RT 8.1 |
| Microsoft | 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 | Microsoft Windows Server 2019 | (Server Core installation) |
| Microsoft | Microsoft Windows Server 2012 | (Server Core installation) |
| Microsoft | Microsoft Windows 8.1 | 32-bit systems x64-based systems |
| Microsoft | Microsoft Windows Server 2016 | (Server Core installation) |
| Microsoft | 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 | 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 | Microsoft Windows 10 Servers | version 1709 (Server Core Installation) version 1803 (Server Core Installation) |
References
2 LinksRecord Details
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