EUVD-2026-44051
GHSA-rq3f-h4px-xmg6
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Local vector and low privilege required as exploitation needs an authenticated session; C:H reflects potential exposure of sensitive kernel or overlay-layer data; no integrity or availability impact documented.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Exposure of sensitive information to an unauthorized actor in Windows Overlay Filter allows an authorized attacker to disclose information locally.
AnalysisAI
Information disclosure in the Windows Overlay Filter (WofFilter) kernel-mode driver allows a locally authenticated low-privileged user to read sensitive data they are not authorized to access across Windows 10, Windows 11, and Windows Server 2016 through 2025. The flaw stems from CWE-200 (improper restriction of information to unauthorized actors) within the filter driver's handling of layered filesystem operations. No public exploit code has been identified and no active exploitation is confirmed; however, the high confidentiality impact (C:H) makes this a meaningful stepping stone in multi-stage attacks on shared or multi-tenant Windows systems.
Technical ContextAI
The Windows Overlay Filter (WofFilter.sys) is a kernel-mode file system filter driver built into Windows that supports compressed file delivery, Windows container isolation layering, and WIM-backed virtual disk operations. CWE-200 indicates the driver fails to properly gate access to sensitive data - likely through an improperly secured IOCTL interface, insufficient ACL enforcement on filter-exposed data structures, or improper memory boundary checks when servicing low-privileged callers. CPE strings confirm the vulnerability spans the application-tier filter across Windows 10 versions 1607, 1809, 21H2, and 22H2; Windows 11 versions 24H2, 25H2, and 26H1; and Windows Server 2016, 2019, 2022, and 2025 - all of which ship WofFilter.sys as a standard inbox component. The CVSS vector AV:L/PR:L confirms the root cause is exercisable by any standard authenticated local session without requiring elevated rights.
RemediationAI
Apply vendor-released patches via Windows Update, WSUS, or Microsoft Update Catalog targeting the fixed build floors confirmed by EUVD-2026-44051: Windows 10 1607 and Server 2016 to build 10.0.14393.9339 or later; Windows 10 1809 and Server 2019 to 10.0.17763.9020 or later; Windows 10 21H2 to 10.0.19044.7548 or later; Windows 10 22H2 to 10.0.19045.7548 or later; Windows 11 24H2 to 10.0.26100.8875 or later; Windows Server 2025 to 10.0.26100.33158 or later; Windows 11 25H2 to 10.0.26200.8875 or later; Windows 11 26H1 to 10.0.28000.2525 or later; Windows Server 2022 to 10.0.20348.5386 or later. Full patch guidance is at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50409. No Microsoft-documented workaround exists. Where immediate patching is not feasible, restrict local logon rights to only necessary user accounts (via Group Policy → User Rights Assignment → Allow log on locally), and on Server environments enforce least-privilege by auditing which accounts have interactive or RDP access - this reduces the pool of potential exploiters but does not eliminate the vulnerability in WofFilter.sys itself.
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Same weakness CWE-200 – Information Exposure
View allSame technique Information Disclosure
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External POC / Exploit Code
Leaving vuln.today