CVE-2026-50482: Windows NTFS Buffer Overflow Vulnerability

CVE-2026-50482 Overview

CVE-2026-50482 is a heap-based buffer overflow vulnerability in the Windows New Technology File System (NTFS) driver. An authorized local attacker can exploit the flaw to execute arbitrary code on the affected system. The vulnerability is classified under [CWE-122] Heap-based Buffer Overflow and requires user interaction to trigger successful exploitation.

Successful exploitation leads to compromise of confidentiality, integrity, and availability on the target host. Microsoft published the advisory for this issue on the Microsoft Security Response Center portal.

Critical Impact
Local code execution in the NTFS driver can enable privilege escalation and full compromise of the host operating system.

Affected Products

Microsoft Windows (NTFS driver component)
Refer to the Microsoft CVE-2026-50482 Advisory for the authoritative list of affected builds
No additional CPE URIs were published in the NVD entry at time of writing

Discovery Timeline

2026-07-14 - CVE-2026-50482 published to NVD
2026-07-15 - Last updated in NVD database

Technical Details for CVE-2026-50482

Vulnerability Analysis

The vulnerability resides in the Windows NTFS file system driver. NTFS handles on-disk data structures such as the Master File Table (MFT), file records, and attribute lists. A heap-based buffer overflow in this code path allows an authorized attacker to write past the bounds of an allocated heap buffer within kernel or driver memory.

Exploitation requires local access with low privileges and user interaction. A typical trigger involves inducing a user to mount, open, or otherwise interact with a crafted NTFS volume or file. Once triggered, the overflow corrupts adjacent heap metadata or object pointers, giving the attacker a primitive for arbitrary code execution.

Microsoft has not disclosed the specific function or parsing routine involved. The Microsoft advisory is the authoritative reference for affected component versions.

Root Cause

The root cause is improper validation of the size of an input buffer relative to the destination heap allocation inside NTFS parsing logic. When the driver processes malformed on-disk structures, it copies attacker-controlled data beyond the intended allocation boundary. This condition falls under [CWE-122] Heap-based Buffer Overflow.

Attack Vector

The attack vector is local. An authenticated attacker with low privileges must convince a user to interact with a malicious NTFS artifact, such as a VHD, ISO, or removable NTFS volume. Once the volume is mounted or the file is parsed, the malformed structure reaches the vulnerable code path and triggers the overflow.

The vulnerability manifests in the NTFS driver's on-disk structure parsing routines. See the Microsoft CVE-2026-50482 Advisory for technical details on the affected component.

Detection Methods for CVE-2026-50482

Indicators of Compromise

Unexpected mounting of VHD, VHDX, or ISO files containing NTFS volumes from user-writable locations such as %TEMP% or the Downloads folder
System crashes or bug checks referencing ntfs.sys following user interaction with an untrusted file or volume
Kernel-mode process spawns or token manipulation immediately after NTFS volume mount events

Detection Strategies

Monitor Windows event logs for repeated NTFS file system errors (Event IDs 55, 130, 137) that may indicate exploitation attempts
Correlate mount events for removable or virtual NTFS volumes with subsequent privileged process creation
Alert on kernel crashes attributed to ntfs.sys in Windows Error Reporting (WER) telemetry

Monitoring Recommendations

Track process creation events where the parent chain originates from a mounted virtual disk image
Audit Group Policy and endpoint controls that permit users to mount arbitrary VHD or ISO files
Ingest kernel crash dumps into a centralized analytics pipeline to identify anomalous NTFS driver faults

How to Mitigate CVE-2026-50482

Immediate Actions Required

Apply the Microsoft security update referenced in the Microsoft CVE-2026-50482 Advisory as soon as it is available for your build
Restrict the ability of standard users to mount VHD, VHDX, and ISO files where not required for business function
Enforce application control policies that block execution of unsigned binaries launched from mounted virtual volumes

Patch Information

Microsoft has published guidance and update information on the Microsoft Security Response Center portal. Administrators should consult the Microsoft CVE-2026-50482 Advisory to identify the correct security update for each affected Windows version and deploy through Windows Update, WSUS, or Microsoft Intune.

Workarounds

Block delivery of container file formats (.iso, .img, .vhd, .vhdx) at the email gateway and web proxy
Use Attack Surface Reduction (ASR) rules and SmartScreen to reduce user exposure to untrusted mountable images
Apply the principle of least privilege so that standard users cannot elevate to administrative contexts following a local code execution primitive

bash

# Example: block user mounting of ISO/VHD via Group Policy registry setting
reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows\DeviceInstall\Restrictions" /v DenyDeviceIDs /t REG_DWORD /d 1 /f
reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows\Explorer" /v NoUseStoreOpenWith /t REG_DWORD /d 1 /f