CVE-2018-8639
Published: 12 December 2018
Summary
CVE-2018-8639 is a high-severity Improper Resource Shutdown or Release (CWE-404) vulnerability in Microsoft Windows Server 2008. Its CVSS base score is 7.8 (High).
Operationally, ranked in the top 3.0% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and AC-6 (Least Privilege).
Deeper analysis
An elevation of privilege vulnerability exists in the Win32k component of Windows when it fails to properly handle objects in memory. The issue, tracked as CVE-2018-8639, affects Windows 7, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows 8.1, Windows RT 8.1, Windows Server 2016, Windows Server 2019, Windows 10, and Windows 10 Servers. It carries a CVSS 3.1 base score of 7.8 and is distinct from the related CVE-2018-8641.
A local attacker with low privileges can exploit the flaw without user interaction to obtain full control over the affected system, resulting in complete loss of confidentiality, integrity, and availability. The vulnerability stems from improper object handling classified under CWE-404 and can be triggered through crafted interactions with the Win32k kernel-mode driver.
Microsoft has published guidance in its security advisory for CVE-2018-8639, and the flaw appears in the CISA Known Exploited Vulnerabilities catalog, confirming observed in-the-wild exploitation. Organizations should apply the vendor-supplied updates referenced in the Microsoft Security Response Center advisory to address the issue.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2018-20250
Vulnerability details
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…
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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.
- CWE(s)
- KEV Date Added
- 03 March 2025
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires applying the vendor patches that remediate the Win32k object-handling flaw before exploitation can succeed.
Enforces least-privilege execution so a low-privileged local attacker cannot reach the Win32k code path with sufficient rights to escalate.
Implements memory-protection safeguards that can block or contain the improper object handling exploited inside the Win32k kernel driver.