Race condition in Windows and Windows Server - CVE-2026-49803
Published: July 17, 2026
Vulnerability identifier: #VU137981
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-49803
CWE-ID: CWE-362
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Microsoft
Affected software:
Windows
Windows Server
Windows
Windows Server
Detailed vulnerability description
The vulnerability allows a local user to escalate privileges.
The vulnerability exists due to a race condition in Windows AppX Deployment Service when performing concurrent execution using shared resources. A local user can trigger concurrent operations to escalate privileges.
Successful exploitation requires winning a race condition and may result in SYSTEM privileges.
How to mitigate CVE-2026-49803
Install security update from vendor's website.