CVE-2026-102227 in Windows
Summary
by MITRE • 10/13/2026
Heap-based buffer overflow in Windows Resilient File System (ReFS) allows an authorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified involves a heap-based buffer overflow within the Microsoft Windows Resilient File System, commonly known as ReFS. This component is responsible for managing file system operations on volumes formatted with this modern storage architecture, which offers features such as data integrity and scalability. The core technical flaw stems from improper memory management during specific input processing sequences handled by the ReFS driver. When an authorized user triggers a particular operation that involves malformed or excessively large inputs, the system fails to adequately validate buffer boundaries before writing data to allocated heap memory. This lack of bounds checking allows an attacker to write beyond the intended limits of the allocated buffer, overwriting adjacent memory structures on the heap.
The operational impact of this vulnerability is severe because it permits local code execution with the privileges of the authenticated user. Since ReFS operates at a low level within the operating system kernel space or high-privilege driver context, exploiting this flaw can lead to arbitrary code execution. An attacker who successfully exploits this condition could install programs, view, change, or delete data, or create new accounts with full user rights. If the affected account is configured with elevated privileges, such as Administrator level, an attacker may gain complete control over the compromised system. This capability enables further lateral movement within a network environment if the machine serves as a pivot point for additional attacks against other systems.
From a classification perspective, this vulnerability aligns with CWE-122, which denotes a heap-based buffer overflow. The exploitation technique typically involves manipulating memory layout to achieve control flow hijacking or arbitrary write primitives, often categorized under ATT&CK techniques related to privilege escalation and execution of native applications. Because the attack requires local access and authentication, it is classified as an insider threat vector rather than a remote code execution vulnerability. This distinction highlights that mitigation strategies must focus on strict user permission management and monitoring of file system activities by privileged accounts rather than just network perimeter defenses.
Mitigation for this issue primarily relies on applying the security update provided by Microsoft to patch the underlying memory handling logic in the ReFS driver. Organizations should ensure that all systems utilizing ReFS volumes are updated with the latest cumulative updates or standalone patches addressing this specific CVE. In addition to patching, implementing least privilege principles is critical; users who do not require administrative rights for file system operations should be restricted from accessing sensitive areas of the disk where such exploits might yield higher privileges. Furthermore, deploying endpoint detection and response solutions can help identify anomalous behavior patterns associated with heap corruption attempts or unauthorized memory access, providing an additional layer of defense against exploitation even if a patch is delayed.