Critical - CVSS 9.8
Known Ransomware Use
Added 3/3/2025

Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability

CVE-2018-8639
Action was due by: 3/24/2025
CISA Known Exploited Vulnerability

This vulnerability is part of CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating active exploitation in the wild. It has been observed in ransomware campaigns.

Overview

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.

Vendor

Microsoft

Product

Windows

Category

Operating System
Technical Details

Affected Versions

See vendor advisory

Technical Description

This vulnerability was identified in Windows by Microsoft. 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.

Exploitability

High - Known ransomware exploitation

Impact

Complete system compromise possible

Additional Notes

https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2018-8639 ; https://nvd.nist.gov/vuln/detail/CVE-2018-8639

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.

Due Date: 3/24/2025