CVE-2026-49794 in Windows
Summary
by MITRE • 07/14/2026
Out-of-bounds read in Windows USB Audio Class driver (usbaudio.sys) allows an unauthorized attacker to disclose information with a physical attack.
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Analysis
by VulDB Data Team • 07/15/2026
The vulnerability resides within the Windows USB Audio Class driver component known as usbaudio.sys which handles audio device communications over USB interfaces. This out-of-bounds read flaw represents a critical security weakness that can be exploited through physical access attacks, where an unauthorized adversary gains direct hardware interaction capabilities with a target system. The vulnerability manifests when the driver processes malformed USB audio descriptors or malformed audio data streams without proper bounds checking mechanisms, allowing memory reads beyond allocated buffer boundaries. Such a condition creates opportunities for information disclosure attacks where attackers can extract sensitive data from kernel memory regions that should remain protected from user-mode access.
The technical implementation of this vulnerability involves the driver's insufficient validation of input parameters received from USB audio devices during enumeration or data transfer operations. When a malicious USB device or compromised audio hardware sends malformed descriptors containing oversized or improperly formatted data structures, the usbaudio.sys component fails to validate array indices or buffer lengths before accessing memory locations. This fundamental flaw aligns with CWE-129 Input Validation and CWE-787 Out-of-bounds Write or Read categories within the Common Weakness Enumeration framework, demonstrating how inadequate bounds checking can lead to memory corruption vulnerabilities. The attack vector requires physical proximity to the target system since USB connections provide direct hardware access points that cannot be mitigated through network-based security controls.
Operationally this vulnerability poses significant risks to organizations as it enables attackers with physical access to potentially extract sensitive information from system memory, including cryptographic keys, authentication tokens, or other confidential data stored in kernel space. The impact extends beyond simple information disclosure since the extracted data could facilitate further attacks such as credential theft, privilege escalation, or system compromise. According to ATT&CK framework category T1059 Command and Scripting Interpreter, attackers leveraging this vulnerability might use the leaked information to conduct more sophisticated attacks against the target environment. The physical access requirement makes this vulnerability particularly concerning for mobile devices, laptops, and systems located in unsecured environments where adversaries can easily connect malicious USB peripherals.
Mitigation strategies should focus on both immediate defensive measures and long-term architectural improvements. Microsoft has released security updates addressing this specific vulnerability through Windows Update mechanisms, requiring system administrators to deploy patches promptly across all affected systems. Organizations should also implement physical security controls such as USB port restrictions, device whitelisting policies, and mandatory access controls to prevent unauthorized USB device connections. Network segmentation and endpoint detection systems can help identify anomalous USB activity patterns that might indicate exploitation attempts. Additionally, kernel-mode code reviews and static analysis tools should be employed to detect similar bounds checking vulnerabilities in other driver components, ensuring comprehensive protection against similar attack vectors. The vulnerability demonstrates the critical importance of robust input validation in kernel-level drivers where memory corruption issues can lead to complete system compromise rather than simple denial-of-service conditions.