CVE-2026-49183 in Windows
Summary
by MITRE • 07/14/2026
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Clipboard Server allows an authorized attacker to elevate privileges locally.
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Analysis
by VulDB Data Team • 07/14/2026
A critical race condition vulnerability exists in the Windows Clipboard Server component that enables local privilege escalation through improper synchronization of concurrent access to shared resources. This vulnerability falls under the CWE-362 category, which specifically addresses race conditions occurring during concurrent execution with shared resources. The flaw manifests when multiple processes attempt to access clipboard data simultaneously without adequate locking mechanisms or atomic operations, creating opportunities for malicious code to manipulate shared memory structures.
The technical implementation of this vulnerability exploits the clipboard server's handling of inter-process communication and shared memory segments that store clipboard data. When an authorized local attacker executes malicious code concurrently with legitimate clipboard operations, they can manipulate the timing and sequence of access to shared resources such as clipboard memory buffers, data structures, or registry entries. This race condition allows the attacker to inject malicious payloads or modify existing clipboard content in ways that trigger privilege escalation when the system processes these manipulated data structures.
The operational impact of this vulnerability is significant for local attackers who already possess user-level privileges on Windows systems. Once exploited, the vulnerability can elevate privileges to SYSTEM level, providing complete control over the affected system and enabling further lateral movement within network environments. The attack requires minimal privileges since the attacker only needs local access to execute malicious code that can trigger the race condition through concurrent clipboard operations or by manipulating clipboard data in a timing-sensitive manner.
Security mitigations for this vulnerability should focus on implementing proper synchronization mechanisms such as mutex locks, semaphores, or atomic operations when accessing shared clipboard resources. Microsoft has addressed similar issues through regular security updates and patches that enforce proper locking protocols around clipboard server components. Organizations should maintain current patch levels, implement application whitelisting to prevent unauthorized code execution, and monitor for suspicious clipboard access patterns. The vulnerability aligns with ATT&CK technique T1068 which covers local privilege escalation through race conditions in Windows systems, making it a target for both automated exploitation tools and advanced persistent threat actors seeking to establish persistent system-level access.