EUVD-2026-43942
GHSA-p2ww-x77q-j883
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local EoP needing a standard-user foothold (AV:L/PR:L) via a low-complexity link-following race that yields SYSTEM, giving full C/I/A impact.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Improper link resolution before file access ('link following') in Windows Projected File System allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows Projected File System (ProjFS) driver lets an authenticated low-privileged attacker abuse a symbolic-link/junction race (CWE-59 link following) to redirect a privileged file operation and gain SYSTEM-level rights across Windows 10 (1809-22H2), Windows 11 (24H2/25H2/26H1), and Windows Server 2019/2022/2025. Microsoft has released a patch; there is no public exploit identified at time of analysis and the flaw is not listed in CISA KEV.
Technical ContextAI
Projected File System (ProjFS) is the Windows component that presents a virtualized/on-demand filesystem namespace, most notably used by Git Virtual File System (GVFS) and similar 'projected' data providers, backed by a kernel-mode driver (PrjFlt.sys) that resolves paths on behalf of callers. The root cause is CWE-59, 'Improper Link Resolution Before File Access (Link Following)': the component follows a symbolic link, junction, or reparse point without safely validating the final target, so a low-privileged user can substitute a link that redirects a privileged file create/write/delete to a location they do not own. The affected products per CPE are the current Windows client and server SKUs (Windows 10 1809/21H2/22H2, Windows 11 24H2/25H2/26H1, Windows Server 2019/2022/2025, including Server Core), indicating the vulnerable driver ships in the base OS rather than an optional add-on.
RemediationAI
Patch available per vendor advisory - apply the Microsoft security update for CVE-2026-50469 to every affected SKU via Windows Update / WSUS / the Microsoft Update Catalog; the exact fixed build numbers per Windows version are listed at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50469 (specific patched build numbers were not provided in this input, so consult the MSRC page for the KB matching each OS version). No independent vendor workaround was published in the available data; because exploitation depends on the ProjFS driver, environments that do not use projected-filesystem features (e.g., GVFS/VFS for Git) can reduce exposure by not enabling the 'Windows Projected File System' optional feature, though this will break any application relying on filesystem virtualization. As general compensating controls until patching completes, restrict interactive/standard-user logon on multi-tenant and terminal-server hosts and monitor for anomalous reparse-point/junction creation, accepting that these only narrow rather than close the local attack surface.
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View allSame technique Information Disclosure
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External POC / Exploit Code
Leaving vuln.today