CVE-2026-50321 in Windows
Summary
by MITRE • 07/14/2026
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows USB Driver allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/15/2026
This vulnerability represents a classic race condition flaw in the windows usb driver component that enables local privilege escalation through improper synchronization of concurrent execution paths. The underlying issue occurs when multiple threads or processes attempt to access shared resources within the usb driver without adequate mutual exclusion mechanisms, creating opportunities for malicious code execution and privilege elevation. The vulnerability specifically manifests in the kernel-mode driver code where usb device handling operations are performed concurrently, allowing an attacker with local user privileges to manipulate timing conditions and exploit the lack of proper locking mechanisms.
The technical implementation involves the usb driver's failure to properly synchronize access to shared data structures during device enumeration and resource allocation phases. When multiple threads simultaneously process usb device events or access driver internal state variables, the absence of adequate semaphore or mutex controls creates windows where malicious code can interfere with legitimate operations. This race condition typically occurs during device attachment or removal scenarios where the driver maintains shared state information that gets modified concurrently by different execution paths.
From an operational perspective this vulnerability allows an authorized attacker to escalate privileges from standard user level to system level through carefully crafted timing attacks and resource manipulation. The attacker must first establish a local presence on the target system, then exploit the race condition by creating conditions where concurrent access to usb driver resources can be controlled or predicted. The attack vector relies on the attacker's ability to monitor system timing and resource states while simultaneously triggering usb device operations that expose the race condition.
The vulnerability aligns with common weakness enumeration cw 367 which specifically addresses time-of-check to time-of-use issues in operating system components, particularly those involving kernel-mode drivers. It also maps to attack technique t1068 from the mitre att&ck framework under privilege escalation through local exploitation of system vulnerabilities. The impact extends beyond simple privilege escalation as it can enable further lateral movement and persistence within the compromised system environment.
Mitigation strategies should focus on implementing proper synchronization mechanisms throughout the usb driver codebase including mutex locks, semaphores, or other mutual exclusion primitives for all shared resource access. System administrators should ensure timely patching of affected windows versions through microsoft security updates, while developers must conduct thorough code reviews to identify and remediate similar race conditions in kernel-mode components. Additional protective measures include enabling driver signature enforcement and restricting local user privileges where possible to limit the potential impact of such vulnerabilities.