Microsoft Security Response CenterCVE-2026-49784

Microsoft Windows App Store Elevation of Privilege Vulnerability

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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7.0CVSS out of 10High severity

Scope

What the vendor says is affected

Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for x64-based Systems
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows Server 2022
Windows 10 Version 21H2 for 32-bit Systems
Windows 10 Version 21H2 for ARM64-based Systems
Windows 10 Version 21H2 for x64-based Systems
Windows 10 Version 22H2 for x64-based Systems
Windows 10 Version 22H2 for ARM64-based Systems
Windows 10 Version 22H2 for 32-bit Systems
Windows Server 2025 (Server Core installation)
Windows 11 Version 25H2 for ARM64-based Systems
Windows 11 Version 25H2 for x64-based Systems
Windows 11 Version 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows Server 2025
Windows 11 version 26H1 for x64-based Systems
Windows 11 Version 26H1 for ARM64-based Systems
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows Server 2016
Windows Server 2016 (Server Core installation)

Versions the vendor lists as fixed

10.0.17763.9020
10.0.20348.5386
10.0.19044.7548
10.0.19045.7548
10.0.26100.33158
10.0.26200.8875
10.0.26100.8875
10.0.28000.2525
10.0.14393.9339

Next step

What the vendor recommends

Install KB5099538. Install KB5099540. Install KB5099539. Install KB5099536. Install KB5101650. Install KB5101649. Install KB5099535.

Review the complete instructions on the vendor's site

Timeline

When this advisory changed

Jul 14, 2026 at 7:00 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
Sep 2, 2026 at 11:20 PM UTC
Added to SecurityAlert
We collected the advisory from the official source.
Sep 3, 2026 at 5:25 AM UTC
Confirmed at the source
Our collector saw this advisory during a later source check.

Vulnerabilities

CVEs named in this advisory

CVE-2026-49784View CVSS, KEV, EPSS, and threat context

Source

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Vendor: Microsoft Security Response Center
Advisory ID: CVE-2026-49784
Last source check: Sep 13, 2026 at 2:40 AM UTC

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Your environment

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What the vendor says is affected

Versions the vendor lists as fixed

What the vendor recommends

When this advisory changed

CVEs named in this advisory

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