Local privilege escalation via AppX deployment race
Published Jul 14, 2026 · Updated Jul 14, 2026
Race condition in Microsoft Windows AppX Deployment Service allows local users with low privileges to elevate privileges on affected builds. The service concurrently accesses a shared deployment resource without proper synchronization; Microsoft has not disclosed the resource or code path. Exploitation requires local low-privileged access and a difficult-to-win race, and successful exploitation grants elevated control over the host.
Summary
What happened
Race condition in Microsoft Windows AppX Deployment Service allows local users with low privileges to elevate privileges on affected builds. The service concurrently accesses a shared deployment resource without proper synchronization; Microsoft has not disclosed the resource or code path. Exploitation requires local low-privileged access and a difficult-to-win race, and successful exploitation grants elevated control over the host.
The record
- CVE
- CVE-2026-49803
- Published
- Jul 14, 2026
- Updated
- Jul 14, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-362, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 14, 2026CVE publishedPublication date reported by the CVE source.
- Jul 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.9020
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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