Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local, low-complexity EoP by an authenticated user (AV:L/AC:L/PR:L, UI:N); kernel-context compromise yields full C/I/A impact within an unchanged scope.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Untrusted pointer dereference in Windows Resilient File System (ReFS) allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in Microsoft Windows Resilient File System (ReFS) lets an authenticated local attacker gain elevated (SYSTEM-level) privileges by triggering an untrusted pointer dereference in the ReFS driver. It affects a broad range of Windows 10, Windows 11, and Windows Server 2016-2025 builds. Microsoft has released a patch; there is no public exploit identified at time of analysis and it is not listed in CISA KEV, so risk is currently patch-and-move rather than emergency.
Technical ContextAI
ReFS (Resilient File System) is Microsoft's newer-generation filesystem, implemented as a kernel-mode driver and used primarily on Windows Server (Storage Spaces, backup targets, large data volumes) and available on modern Windows client editions. The root cause is CWE-822 (Untrusted Pointer Dereference): the driver dereferences a pointer whose value is derived from data the attacker can influence, rather than validating it against a trusted source. Because filesystem parsing runs in kernel context, a controlled dereference of attacker-influenced memory can corrupt kernel state and be steered into a privilege-escalation primitive. The CPE set confirms the affected surface spans Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2016 through 2025 including Server Core installations.
RemediationAI
Apply the Microsoft security update for your specific Windows/Windows Server build (Patch available per vendor advisory) - see https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50441 for the exact fixed build per SKU, as precise fixed version numbers are not included in the provided data. Because exploitation requires an existing local, authenticated foothold, meaningful compensating controls until patching is complete include restricting interactive and local logon rights on ReFS-hosting servers to trusted administrators, and enforcing least privilege so standard users cannot run arbitrary local code. Where operationally acceptable, hosting sensitive volumes on NTFS instead of ReFS removes exposure to this specific driver path, but that is a disruptive migration and only appropriate for new deployments, not a quick mitigation. Prioritize patching ReFS-enabled backup and storage servers where the driver is actively in use.
More in Windows 10 Version 1607
View allRemote code execution in Windows IKE Extension (Internet Key Exchange) via double free memory corruption allows unauthen
Local privilege escalation in Microsoft Active Directory Federation Services (AD FS) lets an already-authenticated low-p
Windows Shell protection mechanism failure (CVE-2026-32202) allows remote attackers to perform spoofing attacks over a n
Local privilege escalation in the Microsoft Windows Kernel allows an unauthorized attacker to gain elevated (SYSTEM-leve
Local code execution in the Windows DHCP Client service stems from a use-after-free (CWE-416) memory-corruption flaw aff
Remote code execution in the Microsoft Windows DHCP Server role allows an unauthenticated network attacker to run arbitr
Local code execution in the Windows Media component of supported Windows 10, Windows 11, and Windows Server (2016 throug
Local privilege escalation via heap-based buffer overflow in the Windows Message Queuing (MSMQ) Queue Manager component
Local privilege escalation in Microsoft Windows Win32K lets an authenticated low-privileged user corrupt kernel heap mem
Local privilege escalation in the Windows NTFS file system driver lets an authenticated low-privileged user win a race c
Elevation of privilege in the Windows Hyper-V virtual network switch (VMSwitch) lets an authenticated attacker operating
Remote code execution in Microsoft Windows Remote Desktop (RDP) allows an unauthorized network attacker to run arbitrary
Same weakness CWE-822 – Untrusted Pointer Dereference
View allSame technique Information Disclosure
View allShare
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-44052
GHSA-p772-w8jr-9x5v