EUVD-2026-44049
GHSA-49jm-rrr5-6685
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local EoP requiring an authenticated low-privileged foothold (AV:L, PR:L, AC:L, UI:N); successful kernel elevation yields full C/I/A impact on the same host (S:U).
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Incorrect conversion between numeric types in Windows NTFS allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows NTFS file-system driver lets an authenticated low-privileged user gain elevated (likely SYSTEM) privileges by exploiting an incorrect conversion between numeric types (CWE-681). Affected platforms span Windows 10 (1607 through 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2012 through 2025. Microsoft reported the flaw and has shipped a patch; there is no public exploit identified at time of analysis and it is not listed in CISA KEV.
Technical ContextAI
The vulnerability resides in NTFS, the default on-disk file system for modern Windows, implemented largely in the kernel-mode driver ntfs.sys. The root cause is CWE-681 (Incorrect Conversion between Numeric Types) - a value is converted between numeric types (e.g., signed/unsigned or wider/narrower integers) in a way that misrepresents the intended value, which can corrupt length, offset, or size calculations used when parsing or manipulating file-system structures. When such a miscalculated value drives memory operations in the kernel, it can lead to out-of-bounds access or memory corruption that is leveraged to run attacker-controlled logic at kernel privilege. The CPE data confirms the affected code is present across the client Windows 10/11 line and the Windows Server 2012-2025 line, consistent with a shared core file-system component rather than an edition-specific feature.
RemediationAI
Patch available per vendor advisory: apply the Microsoft security update for CVE-2026-50402 to every affected Windows client and server SKU via Windows Update, WSUS, or your patch-management tooling, and consult https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50402 for the exact patched build number for each affected version. No exact fix version string was supplied in the input, so confirm the per-SKU KB/build directly from the MSRC page before deploying. Because exploitation requires an authenticated local foothold, effective compensating controls until patching completes include enforcing least privilege and removing unnecessary interactive/local logon rights, restricting who can execute untrusted code on servers, and prioritizing multi-user or shared hosts (RDS, jump boxes, terminal servers) where low-privileged users are present - the trade-off is that these controls reduce but do not eliminate risk, since any local low-privileged account remains a potential launch point.
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Same weakness CWE-681 – Incorrect Conversion between Numeric Types
View allSame technique Information Disclosure
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External POC / Exploit Code
Leaving vuln.today