MSRC-CVE-2026-42900 — Microsoft Windows App Store Elevation of Privilege Vulnerability

Summary

Impact: Elevation of Privilege. Microsoft rating: Important. Not known to be exploited — Exploitation Unlikely. Customer action: Required.

Details

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation of this vulnerability requires an attacker to win a race condition.

Security updates
10.0.17763.9020 — https://support.microsoft.com/help/5099538
10.0.20348.5386 — https://support.microsoft.com/help/5099540
10.0.19044.7548 — https://support.microsoft.com/help/5099539
10.0.26100.33158 — https://support.microsoft.com/help/5099536
10.0.26200.8875 — https://support.microsoft.com/help/5101650
10.0.28000.2525 — https://support.microsoft.com/help/5101649
10.0.14393.9339 — https://support.microsoft.com/help/5099535

Vulnerabilities 1

High 8.1

CVE-2026-42900

Microsoft Windows App Store Elevation of Privilege Vulnerability

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows App Store allows an unauthorized attacker to elevate privileges over a network.

Microsoft Windows Server 2019 Windows Server 2019 (Server Core installation) Windows 10 Version 1809 Windows

Jul 14, 2026

Revision history

2026-07-14 #1
Information published.

References

CVE-2026-42900 Microsoft Windows App Store Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42900
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss