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Local artifact-parsing bug needing no privileges but user interaction to open/mount crafted NTFS content; kernel memory corruption yields full C/I/A impact.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Integer underflow (wrap or wraparound) in Windows NTFS allows an unauthorized attacker to execute code locally.
AnalysisAI
Local code execution in the Microsoft Windows NTFS file-system driver lets an attacker run arbitrary code by inducing a victim to interact with a specially crafted NTFS artifact (e.g., a malicious volume, VHD, or file). The flaw stems from an integer underflow (CWE-191) and spans a broad range of Windows client and server builds from Windows Server 2012 through Windows Server 2025 and Windows 10/11. Microsoft has released a patch; there is no public exploit identified at time of analysis and the issue is not listed in CISA KEV.
Technical ContextAI
NTFS is the default file system for all supported Windows editions, implemented in the kernel-mode driver ntfs.sys, which parses on-disk metadata structures (MFT records, attribute headers, run lists, index buffers). CWE-191 (integer underflow/wraparound) here means a length or size field is decremented below zero and wraps to a very large unsigned value, which then drives an out-of-bounds memory operation during parsing of attacker-controlled file-system structures. Because parsing occurs in kernel context when a volume is mounted or a file is accessed, successful memory corruption can yield code execution in a highly privileged context. The affected CPEs enumerate a wide matrix of Microsoft OS versions: Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2012/2012 R2/2016/2019/2022/2025 including Server Core installations.
RemediationAI
Apply the Microsoft security update for CVE-2026-50308 (Patch available per vendor advisory) via Windows Update or WSUS for each affected OS build; the authoritative fix and per-version KB numbers are published at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50308. Exact fixed build numbers were not included in the input data, so pull them from that MSRC page before deployment. As compensating controls until patching completes, restrict the ability to mount untrusted volumes and disable auto-mounting of removable media and VHD/ISO files (trade-off: may disrupt legitimate removable-media and virtualization workflows), block or quarantine untrusted disk images and NTFS artifacts at the email/web gateway, and enforce user awareness so staff do not open or mount files from untrusted sources (trade-off: relies on user behavior and does not eliminate the flaw). These mitigations reduce exposure to the required user-interaction trigger but are not substitutes for the vendor patch.
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Same weakness CWE-191 – Integer Underflow
View allSame technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-43817
GHSA-hqpm-2xx6-93pp