CVE-2018-8639: Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability

Reference page built from the source records below, each shown as its source publishes it. Dataset version ref-910942c03fbe, updated 2026-11-02T23:39:54.475Z.

CISA Known Exploited Vulnerabilities

Name: Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability
Vendor: Microsoft
Product: Windows
Added to the catalog: 2025-03-03
Due date for US federal agencies: 2025-03-24
Weaknesses: CWE-404
Catalog version: 2026.10.30

Microsoft Windows Win32k contains an improper resource shutdown or release vulnerability that allows for local, authenticated privilege escalation. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode.

Required action (CISA)

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Ransomware use: CISA marks this vulnerability as known to be used in ransomware campaigns. CISA does not say which group used it.

Links in CISA's notes

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status: Analyzed
Published: 2018-12-12T00:29:01.840
Last modified: 2026-06-17T02:05:14.420
Weaknesses: CWE-404

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.

Metric	Score	Severity	Vector	Scored by
CVSS 3.1	7.8	HIGH	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	[email protected] (Primary)
CVSS 3.1	8.4	HIGH	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)
CVSS 2.0	7.2	HIGH	AV:L/AC:L/Au:N/C:C/I:C/A:C	[email protected] (Primary)

References

http://www.securityfocus.com/bid/106093 (Broken Link, Third Party Advisory, VDB Entry)
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8639 (Patch, Vendor Advisory)
http://www.securityfocus.com/bid/106093 (Broken Link, Third Party Advisory, VDB Entry)
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8639 (Patch, Vendor Advisory)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8639 (US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:41:43.468Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2018-8639

CVE record

Assigner: microsoft
State: PUBLISHED
Published: 2018-12-12T00:00:00.000Z
Updated: 2025-10-21T23:45:46.009Z
Problem types: Elevation of Privilege; Information Disclosure

References

Read on 2026-11-03T00:37:22.371Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2018/8xxx/CVE-2018-8639.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

CWE-404: Improper Resource Shutdown or Release

Model: Asset Vulnerability Enumeration (acts on Software)
Isolate: Application-based Process Isolation (acts on Subroutine)
Harden: Variable Initialization (acts on Subroutine)
Restore: Restore Software (acts on Software)
Harden: Software Update (acts on Software)
Harden: Trusted Library (acts on Subroutine)
Harden: Domain Logic Validation (acts on Subroutine)
Model: Software Inventory (acts on Software)
Harden: Memory Block Start Validation (acts on Memory Free Function)
Harden: Null Pointer Checking (acts on Memory Free Function)
Harden: Reference Nullification (acts on Memory Free Function)
Harden: Credential Scrubbing (acts on Subroutine)

D3FEND ontology version 1.6.0.

Read on 2026-11-02T23:56:23.123Z under licence d3fend-terms-of-use@f98cbc7e from https://d3fend.mitre.org/api/weakness/cwe/CWE-404.json

MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/

Sources and licences

CISA
Source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30, CC0 1.0. Use of this data does not imply endorsement by CISA or DHS.
CC0 1.0 Universal
National Vulnerability Database (NIST)
This product uses the NVD API but is not endorsed or certified by the NVD.
NVD API Terms of Use (NIST publications in the public domain, 17 U.S.C. 105)
CVE Program, The MITRE Corporation
Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation. CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
CVE Program Terms of Use ("CVE Usage" licence)
MITRE D3FEND
MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/
MITRE D3FEND Terms of Use (site + knowledge graph); source repo MIT

Cite this page

Dragons Eye Ransomware Tracker, "CVE-2018-8639: Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability",
entity page, dataset version ref-910942c03fbe, updated 2026-11-02T23:39:54.475Z,
https://ransomware-tracker.com/cve/CVE-2018-8639 (accessed 2026-11-03).
Underlying source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30.
Underlying source: National Vulnerability Database (NIST), CVE API 2.0, record last modified 2026-06-17T02:05:14.420.
Underlying source: CVE List (CVE Program, The MITRE Corporation), record updated 2025-10-21T23:45:46.009Z.
Underlying source: MITRE D3FEND, ontology version 1.6.0.

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