CVE-2026-49784 in Windows
Summary
by MITRE • 07/14/2026
Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Windows App Store 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 Microsoft Windows App Store implementation that enables local privilege escalation through improper synchronization of shared resources during concurrent execution scenarios. The vulnerability stems from inadequate thread synchronization mechanisms within the app store's internal processes, creating opportunities for malicious code to exploit timing windows and manipulate shared system resources. Attackers with authorized access can leverage this weakness to execute arbitrary code with elevated privileges, potentially gaining SYSTEM level access to the target system.
The technical implementation of this race condition occurs when multiple threads or processes attempt to access and modify shared resources within the Windows App Store component without proper mutual exclusion controls. This allows an attacker to time their malicious operations precisely to coincide with critical resource modifications, effectively hijacking the normal execution flow. The flaw manifests in the way the system handles concurrent access to app installation, update, or configuration files where proper locking mechanisms are either absent or insufficiently implemented. According to CWE-362, this represents a classic concurrent execution race condition vulnerability that occurs when multiple threads or processes access shared resources without adequate synchronization primitives.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with persistent access to system resources and potentially enables further exploitation vectors within the Windows environment. Once elevated to SYSTEM privileges, attackers can modify critical system files, install malicious software, manipulate user accounts, and establish persistence mechanisms that are difficult to detect or remove. The vulnerability is particularly concerning because it requires only authorized local access, making it exploitable by users who already have legitimate system access but not necessarily administrative privileges. This aligns with ATT&CK technique T1068 which covers local privilege escalation through race conditions.
Mitigation strategies should focus on implementing proper synchronization mechanisms including mutexes, semaphores, or other thread-safe constructs to prevent concurrent access to shared resources during critical operations. Microsoft has addressed this vulnerability through security updates that enforce proper resource locking and validation procedures within the App Store component. System administrators should ensure timely patch deployment and consider implementing additional monitoring for suspicious privilege escalation activities. The remediation approach must also include reviewing and strengthening the overall thread safety of applications that handle concurrent access to shared system resources, particularly those with elevated privileges or system-level functionality.