CVE-2018-8639
Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 24 March 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 22.18% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 3 March 2025 · due 24 March 2025 · used in ransomware campaigns
- Weakness
- CWE-404
- Affected
- 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
- Source
- secure@microsoft.com
EPSS 22.2% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2018-8639 ; https://nvd.nist.gov/vuln/detail/CVE-2018-8639
References
- http://www.securityfocus.com/bid/106093Broken Link, Third Party Advisory, VDB Entry
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8639Patch, Vendor Advisory
- http://www.securityfocus.com/bid/106093Broken Link, Third Party Advisory, VDB Entry
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8639Patch, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8639US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.