CVE-2026-49804 in Windows
Summary
by MITRE • 07/14/2026
Heap-based buffer overflow in Windows USB Video Driver allows an unauthorized attacker to elevate privileges with a physical attack.
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Analysis
by VulDB Data Team • 07/14/2026
A heap-based buffer overflow vulnerability exists within the Windows USB Video Driver component that enables unauthorized attackers to achieve privilege escalation through physical access attacks. This vulnerability stems from improper input validation and memory management practices within the driver's handling of USB video device communications. The flaw occurs when the driver processes malformed or oversized data structures from connected USB video devices without adequate bounds checking, leading to memory corruption in heap-allocated buffers. Attackers with physical access to a target system can exploit this weakness by connecting malicious USB devices that trigger the vulnerable code path during device enumeration and communication initialization. The vulnerability specifically manifests when the driver fails to properly validate the size of incoming data packets from USB video devices, allowing attackers to overwrite adjacent memory locations in the heap. This memory corruption can be leveraged to execute arbitrary code with kernel-level privileges, effectively bypassing standard user-mode security controls. The attack vector is particularly concerning because it requires only physical access to the target system, making it accessible through methods such as malicious USB devices, hardware trojans, or other physical attack vectors commonly associated with supply chain compromises or insider threats. This vulnerability directly aligns with CWE-121 heap-based buffer overflow conditions and represents a significant risk under ATT&CK framework category T1068 for escalation of privileges. The impact extends beyond simple privilege elevation as successful exploitation can lead to complete system compromise, data exfiltration, and persistence mechanisms establishment. Organizations should consider implementing USB device whitelisting policies, disabling unnecessary USB functionality, and applying timely security patches from Microsoft to mitigate this risk. Additionally, physical security measures including secure access controls, device monitoring systems, and regular security assessments should be enhanced to prevent unauthorized physical access to critical systems.
The technical implementation of this vulnerability involves the driver's failure to properly validate data structures received from USB video devices during the initialization phase. When a USB video device is connected, the Windows kernel loads the appropriate driver and begins processing device-specific commands and data streams. The heap overflow occurs in the memory management routines responsible for handling video stream parameters, frame size specifications, or configuration data sent by the USB device. Attackers craft malicious USB devices that contain specially formatted data packets designed to exceed the expected buffer sizes allocated by the driver. When the vulnerable code attempts to copy this oversized data into a fixed-size heap buffer without proper bounds checking, it overflows into adjacent memory regions, potentially corrupting critical data structures or executable code. The exploitation process typically involves careful crafting of the USB device firmware to ensure that the overflow payload precisely targets specific memory locations that can be manipulated to redirect execution flow. This type of vulnerability is particularly challenging to detect and prevent because it operates at the kernel level where normal user-mode protections such as address space layout randomization and data execution prevention may be bypassed or insufficiently effective.
Mitigation strategies for this vulnerability encompass multiple layers of defensive measures including immediate patch deployment from Microsoft, system hardening through configuration changes, and enhanced physical security controls. System administrators should prioritize applying the latest Windows updates that contain fixes for this specific driver vulnerability, as Microsoft typically releases patches addressing such kernel-level issues through regular security update cycles. Additional protective measures include implementing USB device filtering policies that restrict which types of USB devices can connect to critical systems, disabling unnecessary USB functionality through group policy settings, and enabling kernel-mode drivers to be signed and verified through Windows Driver Signature Enforcement. Network-based monitoring solutions should be enhanced to detect anomalous USB device connections or unusual patterns in device enumeration activities that might indicate exploitation attempts. Physical security enhancements such as restricted access areas, device tracking systems, and regular inventory audits help prevent unauthorized physical access to target systems. The vulnerability's presence in the USB video driver also highlights the importance of understanding supply chain risks associated with peripheral devices and implementing comprehensive device authentication mechanisms where possible. Organizations should also consider deploying endpoint detection and response solutions that can identify suspicious kernel-level activities or memory corruption patterns indicative of buffer overflow exploitation attempts. Security awareness training for personnel regarding physical security threats and the risks associated with connecting unknown USB devices remains crucial in preventing successful exploitation through this attack vector.