What is the CVSS score of EUVD-2026-44071?

EUVD-2026-44071 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Which versions of Windows ReFS are affected by EUVD-2026-44071?

CVE-2026-50362 is a high-severity vulnerability affecting the Windows ReFS driver across Windows 10, Windows 11, and Windows Server 2016-2025, enabling local code execution when users mount or open a…. A patch is available.

How to fix or mitigate EUVD-2026-44071?

Within 24 hours, inventory all systems running Windows 10, 11, or Windows Server 2016-2025 and assess ReFS usage; prioritize systems with higher user interaction or sensitive data exposure. Within 7 days, obtain Microsoft's vendor-released patch, test it against critical applications in a staging environment, and begin deployment starting with high-risk systems and servers. Within 30 days, complete patching across all Windows 10, 11, and Server systems organization-wide, verify successful deployment through your patch management tools, and document any exceptions for systems unable to patch within the window.

Windows ReFS EUVD-2026-44071

| CVE-2026-50362 HIGH

Heap-based Buffer Overflow (CWE-122)

2026-07-14 microsoft

GHSA-qmfc-cvq2-hfwh

Buffer Overflow Heap Overflow Microsoft Windows Server 2016 Windows Server 2019 Windows Server 2022 Windows Server 2025 Windows 10 Version 1607 Windows 10 Version 1809 Windows 10 Version 21H2 Windows 10 Version 22H2 Windows Server 2016 Server Core Installation Windows Server 2019 Server Core Installation Windows 11 Version 24H2 Windows 11 Version 25H2 Windows 11 Version 26H1 Windows Server 2025 Server Core Installation

7.8

CVSS 3.1 · Vendor: microsoft

Temporal: 6.8

Severity by source

Vendor (microsoft) PRIMARY

7.8 HIGH

AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CIRCL (temporal)

6.8 MEDIUM

cvss

vuln.today AI

7.8 HIGH

Local delivery of a crafted volume (AV:L) that the victim must mount (UI:R) with no auth (PR:N); kernel-context code execution gives full C/I/A impact.

3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Jul 14, 2026 - 21:26 vuln.today

CVE Published

Jul 14, 2026 - 17:07 nvd

HIGH 7.8

DescriptionCVE.org

Heap-based buffer overflow in Windows Resilient File System (ReFS) allows an unauthorized attacker to execute code locally.

AnalysisAI

Local code execution in Microsoft Windows' Resilient File System (ReFS) driver lets an unauthorized attacker run arbitrary code by inducing a victim to mount or open a maliciously crafted ReFS volume (CVE-2026-50362). The flaw affects the ReFS component shipped across Windows 10, Windows 11 (through 26H1), and Windows Server 2016-2025, carries CVSS 7.8, and requires user interaction (UI:R) with no prior authentication (PR:N). Microsoft has released a patch; there is no public exploit identified at time of analysis and it is not listed in CISA KEV.

Technical ContextAI

The vulnerability is a heap-based buffer overflow (CWE-122) in the Resilient File System (ReFS), Microsoft's copy-on-write filesystem used for Storage Spaces, Windows Server data volumes, and Dev Drive. When the ReFS kernel-mode driver parses on-disk metadata structures from a volume, insufficient bounds validation allows attacker-controlled data to write past an allocated heap buffer, corrupting adjacent kernel heap memory. Because the parsing runs in kernel context, controlled corruption of ReFS metadata can be leveraged to hijack execution flow. The affected CPEs enumerate the ReFS-bearing OS builds: Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2016, 2019, 2022, and 2025 including Server Core installations.

RemediationAI

Patch available per vendor advisory - apply the Microsoft security update for CVE-2026-50362 for the specific Windows or Windows Server build in use, which is delivered through the monthly cumulative update; consult https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50362 for the exact fixed build number matching each affected version. Where immediate patching is not possible, reduce exposure by restricting the ability to mount untrusted ReFS volumes: block or restrict auto-mounting of removable media and disk images via Group Policy device installation restrictions, disallow mounting of user-supplied VHD/VHDX and physical volumes on sensitive hosts, and train users not to open or mount storage from untrusted sources. On systems that do not use ReFS these controls have minimal operational impact, but on Storage Spaces or Dev Drive hosts restricting volume mounting may interrupt legitimate storage workflows, so scope the controls to endpoints that handle external media.