EUVD-2026-56652
GHSA-qw63-qw4q-gppx
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local kernel driver flaw exploitable by any authenticated user with no interaction; full C/I/A impact reflects SYSTEM-level privilege gain.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
3DescriptionCVE.org
Integer overflow or wraparound in Windows Projected File System allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in Windows Projected File System (ProjFS) via an integer overflow allows an authenticated local user to gain full SYSTEM-level control over the affected host. The flaw spans a wide range of actively supported Windows releases - from Windows 10 21H2 through Windows 11 26H1, and both Windows Server 2022 and 2025 - making it a broadly applicable post-compromise escalation primitive. No public exploit code or active exploitation has been identified at time of analysis; Microsoft has released patched builds addressing the vulnerability.
Technical ContextAI
Windows Projected File System (ProjFS), introduced in Windows 10 version 1809, is a kernel-mode component that allows user-mode provider applications to expose virtual, on-demand file system namespaces backed by arbitrary data sources (commonly used by Git VFS for Windows and similar tools). CWE-190 (Integer Overflow or Wraparound) identifies the root cause: an arithmetic operation on a size or index value in the ProjFS driver overflows its integer type, producing an unexpectedly small result that causes downstream memory corruption - typically an undersized buffer allocation or an out-of-bounds write. Because ProjFS operates in kernel space, memory corruption at this layer can be leveraged to overwrite kernel data structures and redirect execution to attacker-controlled code running at elevated privilege. Affected CPE targets include Windows 10 (10.0.19044.x, 10.0.19045.x), Windows 11 across multiple release trains (10.0.22631.x, 10.0.26100.x, 10.0.26200.x, 10.0.28000.x), and Windows Server 2022 (10.0.20348.x) and 2025 (10.0.26100.x).
RemediationAI
Apply Microsoft's security update via Windows Update or WSUS immediately, targeting the minimum fixed builds identified in the EUVD advisory: Windows Server 2022 must reach 10.0.20348.5499 or later; Windows 10 21H2 must reach 10.0.19044.7663 or later; Windows 10 22H2 must reach 10.0.19045.7663 or later; Windows 11 23H2 must reach 10.0.22631.7517 or later; Windows 11 24H2 and Server 2025 must reach 10.0.26100.9168 (client) or 10.0.26100.33296 (server) or later; Windows 11 25H2 must reach 10.0.26200.9168 or later; Windows 11 26H1 must reach 10.0.28000.2704 or later. Consult the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62751 for the definitive patch manifest. Where immediate patching is not feasible, a targeted compensating control is to disable the Windows Projected File System optional feature via DISM (Disable-WindowsOptionalFeature -Online -FeatureName Client-ProjFS) on systems where ProjFS is not operationally required - note that this will break VFS for Git and any other ProjFS-dependent applications. Prioritize patching multi-user systems, RDS hosts, and endpoints exposed to lower-trust users.
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Same weakness CWE-190 – Integer Overflow or Wraparound
View allSame technique Buffer Overflow
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External POC / Exploit Code
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