Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Local trigger via crafted volume/file (AV:L) needs a user to mount/open it (UI:R) but no attacker privileges (PR:N); a successful overflow yields full code execution, so C/I/A:H.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Heap-based buffer overflow 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 triggering a heap-based buffer overflow (CWE-122) when Windows parses crafted file-system metadata. The flaw spans a broad range of supported releases, from Windows 10 1607 and Server 2012 through Windows 11 26H1 and Server 2025. It carries a CVSS 7.8 (Important) rating, requires user interaction, has a vendor patch available, and no public exploit identified at time of analysis.
Technical ContextAI
NTFS is the default Windows file-system driver (ntfs.sys) shipping in every modern client and server edition; it parses on-disk metadata such as the Master File Table, index attributes, and reparse points in privileged context. CWE-122 (heap-based buffer overflow) indicates a length or bounds check on attacker-controlled file-system metadata is mishandled, allowing a write past an allocated heap buffer when a crafted volume or file is processed. Because NTFS parsing runs when a volume is mounted or a file is accessed, the corruption occurs during normal handling of malformed structures. The CPE set (cpe:2.3:a:microsoft:windows_10_version_1607 through windows_11_version_26h1, plus windows_server_2012/2012_r2 and their Server Core installations) and the tag list extend coverage to Server 2016, 2019, 2022 and 2025, indicating long-standing shared code across the Windows codebase.
RemediationAI
Patch available per vendor advisory: apply the Microsoft security update for CVE-2026-50448 for each affected edition as documented at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50448 (consult that page for the exact fixed build per Windows/Server version, since precise fixed version numbers were not included in the input data). Prioritize systems where users routinely mount external or untrusted volumes. Where immediate patching is not possible, reduce exposure by restricting the mounting of untrusted media and disk images - for example, disable or restrict auto-mounting of USB storage and block mounting of VHD/VHDX and ISO images via Group Policy and device control; the trade-off is reduced convenience for legitimate removable-media and virtual-disk workflows. User awareness (do not open or mount file-system images from untrusted sources) further limits the UI:R trigger. These are compensating controls only; the update is the definitive fix.
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
View allShare
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-43931
GHSA-vpjv-4254-vv44