Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Requires an existing low-privileged local session (AV:L/PR:L), triggers reliably without user interaction (AC:L/UI:N), and yields SYSTEM-level kernel code execution (C:H/I:H/A:H).
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Heap-based buffer overflow in Windows NTFS allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in the Windows NTFS driver lets an already-authenticated attacker corrupt heap memory to run code at a higher privilege level (typically SYSTEM) on affected Windows 10, Windows 11, and Windows Server builds. Microsoft reported the issue and has shipped a fix; there is no public exploit identified at time of analysis and it is not listed in CISA KEV. With CVSS 7.8 (AV:L/PR:L) it is a valuable post-compromise pivot rather than an initial-access bug.
Technical ContextAI
NTFS is the default on-disk file system driver in every modern Windows release, running in kernel mode as part of the core OS. The flaw is CWE-122, a heap-based buffer overflow: the NTFS driver writes past the bounds of a dynamically allocated kernel heap buffer, likely while parsing attacker-influenced file-system structures or metadata. Because the affected code executes in ring 0, controlled heap corruption can be groomed to overwrite adjacent kernel objects or function pointers, converting a memory-safety bug into arbitrary code execution at kernel privilege. The CPE set covers the Windows kernel/NTFS component across Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2012 through 2025.
RemediationAI
Patch available per vendor advisory: apply the Microsoft cumulative update for your specific Windows/Windows Server build as listed in the MSRC guidance at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56175, which provides the exact patched build number for each affected SKU (no single cross-SKU version string is published). Prioritize multi-user and shared systems (RDP/Citrix hosts, domain controllers, jump boxes) where a low-privileged foothold most easily exists. No specific pre-patch workaround is documented by Microsoft for NTFS heap corruption; because NTFS cannot be disabled, the practical compensating controls are to limit local/interactive logon rights and remove unnecessary standard-user accounts to shrink the pool of attackers who can reach the vulnerable code, and to monitor EDR for suspicious process token elevation - these reduce but do not eliminate exposure and have no functional downside beyond tighter access management.
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-44239
GHSA-fc99-9g2v-hx8x