CVE-2026-69490 in Windows
Summary
by MITRE • 09/09/2026
Out-of-bounds read in Windows USB Mass Storage Class Driver allows an unauthorized attacker to elevate privileges with a physical attack.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as CVE-2024-38067 represents a critical security flaw within the Universal Serial Bus (USB) Mass Storage Class driver, specifically usbstor.sys, in Microsoft Windows operating systems. This defect is classified technically as an out-of-bounds read, which falls under the Common Weakness Enumeration category CWE-125. The core issue arises from improper bounds checking when the driver processes specific USB device descriptors or data structures sent by a connected storage peripheral. When a maliciously crafted USB mass storage device is physically connected to a vulnerable Windows system, the driver fails to validate the length of certain fields before reading them into memory buffers. This lack of validation allows the driver to read beyond the allocated boundaries of internal data structures, potentially exposing sensitive kernel-mode information or causing unpredictable behavior in the operating system's memory management subsystems.
The operational impact of this vulnerability is severe due to its potential for privilege escalation via physical attack vectors. An attacker with direct physical access to a target machine can exploit this flaw by connecting a specially designed USB device that triggers the out-of-bounds read condition. While an out-of-bounds read typically results in information disclosure, in the context of kernel drivers like usbstor.sys, such memory corruption or leakage can often be leveraged as part of a broader exploitation chain to achieve arbitrary code execution with SYSTEM-level privileges. This aligns with MITRE ATT&CK technique T1059, Command and Scripting Interpreter, when combined with subsequent payload delivery, but more directly relates to privilege escalation techniques where an attacker moves from user-level access or physical presence to full control of the operating system kernel. The ability to escalate privileges through a simple USB connection bypasses many network-based security controls, making it particularly dangerous in environments where physical security is not strictly enforced or for devices that are frequently connected to external peripherals such as laptops and portable workstations.
Mitigation strategies must address both software configuration and physical access policies. Microsoft has released patches to correct the bounds checking logic within the USB Mass Storage Class driver, ensuring that all incoming data from USB devices is validated against expected limits before processing. Organizations should prioritize applying these security updates across all endpoints running affected versions of Windows. In addition to patching, implementing strict device control policies through solutions like Endpoint Detection and Response (EDR) or Microsoft Defender for Endpoint can help detect anomalous behavior associated with malicious USB enumeration attempts. Furthermore, enforcing physical access controls remains critical; restricting who can physically connect devices to corporate assets significantly reduces the attack surface for this type of vulnerability. Administrators should also consider disabling unused USB ports where possible through group policy settings to limit exposure to untrusted peripherals. Regular audits of connected hardware and monitoring for unusual kernel-level activity are essential components of a defense-in-depth strategy against physical access-based attacks leveraging driver vulnerabilities.