Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability
Microsoft — Windows 7
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.
8.4
22.3%
Vector breakdown
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- Dec 12, 2018
- Modified
- Oct 21, 2025
- Added to KEV
- Mar 3, 2025
- Federal patch due
- Mar 24, 2025
CISA 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.
Weakness classification
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2018-8639, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2018-8639 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.
References
Frequently asked questions
What is CVE-2018-8639?
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.
How severe is CVE-2018-8639?
CVE-2018-8639 has a CVSS base score of 8.4 out of 10 (CVSS 3.1).
Is CVE-2018-8639 actively exploited in the wild?
Yes. CVE-2018-8639 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Mar 3, 2025, meaning CISA has confirmed evidence of active exploitation. It is also flagged as used in ransomware campaigns.
What is the EPSS score for CVE-2018-8639?
22.3% - meaning FIRST.org's EPSS model estimates a 22.3% probability this vulnerability will be exploited in the wild within 30 days (97% percentile among all scored CVEs).
What type of vulnerability is CVE-2018-8639?
CVE-2018-8639 is classified under CWE-404 (CWE-404 Improper Resource Shutdown or Release).
Cross-checked against
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