CVE-2026-85807 in Windows
Summary
by MITRE • 10/14/2026
Integer overflow or wraparound in Windows USB Video Driver allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified involves a critical integer overflow condition within the Windows USB Video Class driver, specifically affecting how memory buffers are allocated and managed during video stream processing operations. This flaw stems from improper validation of input parameters supplied by user-mode applications or hardware devices interacting with the kernel-level driver components. When an attacker constructs a malicious payload that triggers this arithmetic error, it results in the allocation of a significantly smaller buffer than intended by the application logic. Subsequently, when data is written into this undersized memory region based on the original expected size, a heap-based buffer overflow occurs. This overwriting of adjacent memory structures can corrupt critical kernel data structures or allow for arbitrary code execution within the context of the operating system's most privileged process account.
From a technical perspective, this issue represents a classic instance of CWE-190, which classifies integer overflow or wraparound errors that lead to subsequent security vulnerabilities such as buffer overflows. The root cause lies in the failure of the driver code to properly check for arithmetic saturation before performing memory allocation calculations. In many cases, these drivers handle large data streams from webcams and other video input devices without rigorous bounds checking on size parameters derived from external sources. An attacker with local access can exploit this by sending specially crafted IOCTL requests or injecting malformed USB descriptors that trigger the overflow condition during initialization or streaming phases of the driver's lifecycle.
The operational impact of successfully exploiting this vulnerability is severe, as it facilitates a privilege escalation attack from a low-privileged user context to SYSTEM-level privileges on the affected Windows operating system instances. Once an attacker achieves local code execution with elevated rights, they can bypass standard security controls such as User Account Control and mandatory access policies. This grants unrestricted read-write-execute permissions over the entire file system, registry, and running processes. Consequently, attackers can install persistent backdoors, exfiltrate sensitive data, disable security software, or use the compromised machine as a pivot point for further network intrusions. The ability to execute arbitrary code in kernel mode also opens avenues for advanced evasion techniques that are difficult for endpoint detection solutions to identify due to their deep integration with the operating system core.
Mitigation strategies primarily involve applying vendor-provided security updates and patches released by Microsoft to address this specific flaw within the USB Video Class driver infrastructure. Organizations should prioritize patch management cycles to ensure all endpoints receive these critical fixes promptly. In environments where immediate patching is not feasible, network segmentation can help limit lateral movement if a lower-privileged account were compromised through other vectors. Additionally, enforcing strict application whitelisting and restricting user privileges to the minimum necessary for their roles reduces the attack surface available to potential exploiters. Monitoring system logs for unusual driver loading patterns or unexpected kernel-mode activity may also aid in early detection of exploitation attempts before full compromise occurs.