Actively exploited · Published Dec 12, 2018 · Assigned by microsoft

CVE-2018-8639

High 8.4 Exploited Ransomware

In plain English

A high-severity security flaw in Windows 10 from Microsoft. Attackers are actively exploiting it in the wild (listed by CISA on March 3, 2025). It has been used in ransomware campaigns. The chance it is exploited in the next 30 days is estimated at 22.3% (higher than 98% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Severity (CVSS 3.1)8.4High
Exploit odds (30 days)22.3%top 2.3% of all CVEs
Exploited in the wildYesCISA KEV since Mar 3, 2025
Attack tooling1Public PoC

CISA guidance

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

Federal agencies must remediate by Mar 24, 2025.

Official 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.

Affected products (as reported)

VendorProductVersions
Microsoft Windows 7 32-bit Systems Service Pack 1x64-based Systems Service Pack 1
Microsoft Windows Server 2012 R2 (Server Core installation)
Microsoft Windows RT 8.1 Windows RT 8.1
Microsoft Windows Server 2008 32-bit Systems Service Pack 232-bit Systems Service Pack 2 (Server Core installation)Itanium-Based Systems Service Pack 2x64-based Systems Service Pack 2x64-based Systems Service Pack 2 (Server Core installation)
Microsoft Windows Server 2019 (Server Core installation)
Microsoft Windows Server 2012 (Server Core installation)
Microsoft Windows 8.1 32-bit systemsx64-based systems
Microsoft Windows Server 2016 (Server Core installation)
Microsoft Windows Server 2008 R2 Itanium-Based Systems Service Pack 1x64-based Systems Service Pack 1x64-based Systems Service Pack 1 (Server Core installation)
Microsoft Windows 10 32-bit SystemsVersion 1607 for 32-bit SystemsVersion 1607 for x64-based SystemsVersion 1703 for 32-bit SystemsVersion 1703 for x64-based SystemsVersion 1709 for 32-bit SystemsVersion 1709 for ARM64-based SystemsVersion 1709 for x64-based Systems
Microsoft Windows 10 Servers version 1709 (Server Core Installation)version 1803 (Server Core Installation)

Weakness: CWE-404 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References