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CVE-2018-8639

High 7.8 Exploited in the wild (KEV) Used in ransomware campaigns

Confirmed active exploitation — CISA KEV catalog

Name
Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability
Added to catalog
Remediation due date (US federal)
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.

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.

Metrics

CVSS 3.1
7.8 (HIGH) Score source: NVD CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS — exploit probability
22% (percentile: 98) as of 1 November 2026
CWE
CWE-404

Affected products

microsoft: windows 10 1507; microsoft: windows 10 1607; microsoft: windows 10 1703; microsoft: windows 10 1709; microsoft: windows 10 1803; microsoft: windows 10 1809; microsoft: windows 7; microsoft: windows 8.1; microsoft: windows rt 8.1; microsoft: windows server 2008; microsoft: windows server 2012; microsoft: windows server 2016; microsoft: windows server 2019

References