CVE-2026-96867 in Windows
Summary
by MITRE • 10/14/2026
Out-of-bounds read in Windows NTFS allows an authorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described involves a critical out-of-bounds read flaw within the New Technology File System driver, commonly referred to as ntfs.sys, which is integral to Microsoft Windows operating systems. This component manages file storage and retrieval on NTFS volumes, handling complex metadata structures that define how files are organized on disk. The specific technical flaw arises when the system processes malformed or specially crafted input data related to these filesystem operations. Instead of properly validating the boundaries of memory buffers before reading from them, the driver fails to ensure that the requested read operation remains within allocated limits. This lack of rigorous boundary checking allows an attacker who has already gained local access to trigger a condition where the kernel attempts to read memory addresses outside the intended buffer space. While out-of-bounds reads are often associated with information disclosure vulnerabilities, in this specific context involving low-level system drivers and potential exploitation chains, it serves as a precursor or direct mechanism for arbitrary code execution under certain conditions.
From an operational perspective, the impact of this vulnerability is severe due to its location within the kernel mode environment. Because ntfs.sys operates at ring 0 with unrestricted access to hardware resources and memory, any successful exploitation grants the attacker complete control over the affected system. An authorized local attacker can leverage this flaw to bypass security restrictions such as User Account Control or mandatory integrity levels. By carefully crafting input that triggers the out-of-bounds read, an attacker may be able to leak sensitive kernel data structures which could facilitate further exploitation steps, including heap spraying techniques or information gathering for privilege escalation vectors. In scenarios where the vulnerability is chained with other flaws or utilized in a way that corrupts memory state beyond simple reading, it can lead directly to arbitrary code execution, allowing the compromise of system integrity and confidentiality.
This type of flaw aligns closely with Common Weakness Enumeration identifier CWE-125, which defines out-of-bounds read errors resulting from improper validation of array indices or buffer boundaries. The exploitation path typically involves an attacker providing maliciously constructed file attributes or directory entries that cause the NTFS driver to miscalculate memory offsets. In terms of tactical classification under the MITRE ATT&CK framework, this vulnerability supports techniques related to Privilege Escalation and potentially Initial Access if combined with other vectors like phishing leading to local execution. The attack vector is classified as Local (AV:L), requiring physical or logical access to the machine before exploitation can commence. This underscores the importance of strict endpoint security controls even for authenticated users, as lateral movement within a network often begins with such local privilege escalations.
Mitigation strategies primarily rely on timely application of vendor-provided patches that correct the boundary checking logic within ntfs.sys. System administrators should ensure that all workstations and servers are updated to versions containing these fixes. In environments where patching is not immediately feasible, defense-in-depth measures become critical. These include restricting local administrative privileges to only those users who absolutely require them, thereby reducing the pool of potential attackers capable of triggering the vulnerability. Additionally, deploying endpoint detection and response solutions that monitor for anomalous kernel-mode activity or unusual memory access patterns can help detect exploitation attempts in real-time. Regular auditing of user permissions and enforcing least-privilege principles significantly reduces the attack surface available to local adversaries seeking to exploit filesystem driver flaws.