CVE-2018-8639: Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
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.
Description quoted from the CVE record (assigned by microsoft, published 2018-12-12).
Weakness: CWE-404 Improper Resource Shutdown or Release
How it can be exploited
Exploitable with local access with low attack complexity needing no privileges and no user interaction. Impact: 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
CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: no. Technical impact: total.
- On CISA KEV since
- 2025-03-03
- US federal deadline
- 2025-03-24
- Ransomware use
- Yes
Public exploit evidence (Exploit Observer)
Also known as: BDU:2018-01646, CNNVD-201812-443, CNVD-2019-03921, EUVD-2018-20250, EUVD-2018-20252, GHSA-93mm-g479-2cx4, GHSA-jxw3-833q-c4j7
VEDAS cluster: VEDAS:BEASTLYBUFFALO
Exploit Observer links 2 pieces of public exploit code or detection modules that name this CVE or one of its aliases.
Exploit code and modules (2)
Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.
- Code repository: https://github.com/timwhitez/cve-2018-8639-exp
- Code repository: https://github.com/ze0r/cve-2018-8639-exp
Vulnerability databases and vendor advisories (10)
Catalogue entries, not exploit evidence.
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2018-20250
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2018-20252
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-93mm-g479-2cx4
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-jxw3-833q-c4j7
- Vulnerability database or vendor advisory: https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2018-8639
- Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2018-8639
- Vulnerability database or vendor advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8639
- Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8639
- Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-201812-443
- Vulnerability database or vendor advisory: https://www.cnvd.org.cn/flaw/show/CNVD-2019-03921
29 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.
VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.
Live scores
- EPSS
- 0.222
likely to be attacked soon - VEDAS
- 0.970
strong exploit evidence - On CISA KEV
- Yes, since 2025-03-03
- Detection rule
- Out of scope (local)
Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish.
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Microsoft Windows 7 | version 32-bit Systems Service Pack 1 version x64-based Systems Service Pack 1 | Not stated |
| Microsoft Windows Server 2012 R2 | version (Server Core installation) | Not stated |
| Microsoft Windows RT 8.1 | version Windows RT 8.1 | Not stated |
| Microsoft Windows Server 2008 | version 32-bit Systems Service Pack 2 version 32-bit Systems Service Pack 2 (Server Core installation) version Itanium-Based Systems Service Pack 2 version x64-based Systems Service Pack 2 version x64-based Systems Service Pack 2 (Server Core installation) | Not stated |
| Microsoft Windows Server 2019 | version (Server Core installation) | Not stated |
| Microsoft Windows Server 2012 | version (Server Core installation) | Not stated |
| Microsoft Windows 8.1 | version 32-bit systems version x64-based systems | Not stated |
| Microsoft Windows Server 2016 | version (Server Core installation) | Not stated |
| Microsoft Windows Server 2008 R2 | version Itanium-Based Systems Service Pack 1 version x64-based Systems Service Pack 1 version x64-based Systems Service Pack 1 (Server Core installation) | Not stated |
| Microsoft Windows 10 | version 32-bit Systems version Version 1607 for 32-bit Systems version Version 1607 for x64-based Systems version Version 1703 for 32-bit Systems version Version 1703 for x64-based Systems version Version 1709 for 32-bit Systems version Version 1709 for ARM64-based Systems version Version 1709 for x64-based Systems and 7 more ranges | Not stated |
| Microsoft Windows 10 Servers | version version 1709 (Server Core Installation) version version 1803 (Server Core Installation) | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
Exploit Observer also maps it to: 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.
How to fix it
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.
Vendor guidance:
- https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2018-8639
- https://nvd.nist.gov/vuln/detail/CVE-2018-8639
How to detect it
This bug needs local access to exploit. VEDAS signatures cover remotely exploitable bugs for now, so there is no network rule or remote check for it. Patch it and watch your endpoint telemetry for unusual local activity.
References
Government sources
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8639 (government-resource)
Other references
- 106093 (vdb-entry, x_refsource_BID)
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8639 (x_refsource_CONFIRM)
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.