Cyber Resilience

CVE-2018-8639

Microsoft Windows Server 2008 r2

CISA KEVActive ExploitationEUVD ExploitedRansomware-linked
Published
12 December 2018
Modified
29 October 2025
KEV Added
03 March 2025
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.22 97th percentile
Risk Priority 83 floored blend · peak EPSS

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, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

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

Vulnerability Data

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…

more

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

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.001 OS Exhaustion Flood Impact
Adversaries may launch a denial of service (DoS) attack targeting an endpoint's operating system (OS).
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2018-8611Same product: Microsoft Windows 10 1607both on KEV
CVE-2018-8405Same product: Microsoft Windows 10 1507both on KEV
CVE-2018-8406Same product: Microsoft Windows 10 1507both on KEV
CVE-2018-8120Same product: Microsoft Windows 7both on KEV
CVE-2019-0752Same product: Microsoft Windows 10 1507both on KEV
CVE-2018-8653Same product: Microsoft Windows 10 1507both on KEV
CVE-2019-0676Same product: Microsoft Windows 10 1507both on KEV
CVE-2019-1214Same product: Microsoft Windows 10 1507both on KEV
CVE-2019-0543Same product: Microsoft Windows 10 1507both on KEV
CVE-2019-1367Same product: Microsoft Windows 10 1607both on KEV

Affected Assets

microsoft
windows 10 1507
all versions
microsoft
windows 10 1607
all versions
microsoft
windows 10 1703
all versions
microsoft
windows 10 1709
all versions
microsoft
windows 10 1803
all versions
microsoft
windows 10 1809
all versions
microsoft
windows 7
all versions
microsoft
windows 8.1
all versions
microsoft
windows rt 8.1
all versions
microsoft
windows server 2008
all versions, r2
+3 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-404

Contingency plan updates incorporate proper resource shutdown and release steps, preventing attackers from leveraging incomplete cleanup during recovery scenarios.

addresses: CWE-404

Mandates explicit shutdown of the network connection at session conclusion, directly addressing improper resource release.

addresses: CWE-404

Requires proper shutdown/release procedures that include overwriting or isolating data to block unintended transfer via reused system objects.

addresses: CWE-404

Procedures can mandate orderly shutdown or release of resources when failures occur, preventing improper resource handling after a fault.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly include coding standards for correct resource allocation and release.

DE.CM-09 partial match
prevents

Runtime monitoring can detect resource exhaustion caused by improper shutdown or release.

ID.AM-08 partial match
prevents

Lifecycle management of assets can encompass proper resource release at end-of-life or shutdown.

PR.IR-04 partial match
prevents

Capacity management helps surface leaks from unreleased resources but does not prevent the coding flaw.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Including restart, recovery and media-handling instructions reduces the likelihood that resources or sensitive data will be left in an exposed or improperly released state after a failure.

References