MicrosoftCVE-2026-66802

Microsoft Windows: race condition

CVE-2026-66802 · Published Aug 11, 2026 · updated Aug 20, 2026

High8.1

Fix: upgrade to 10.0.17763.9121 or later (4 fixed versions below)

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Device Health Attestation (DHA) allows an unauthorized attacker to execute code over a network.

Affected versions

Package	Affected	Fixed in
Windows 10 Version 1809 Product	>= 10.0.17763.0, < 10.0.17763.9121	10.0.17763.9121
Windows 11 version 26H1 Product	>= 10.0.28000.0, < 10.0.28000.2704	10.0.28000.2704
Windows Server 2019 Product	>= 10.0.17763.0, < 10.0.17763.9121	10.0.17763.9121
Windows Server 2019 (Server Core installation) Product	>= 10.0.17763.0, < 10.0.17763.9121	10.0.17763.9121
Windows Server 2022 Product	>= 10.0.20348.0, < 10.0.20348.5499	10.0.20348.5499
Windows Server 2025 Product	>= 10.0.26100.0, < 10.0.26100.33296	10.0.26100.33296
Windows Server 2025 (Server Core installation) Product	>= 10.0.26100.0, < 10.0.26100.33296	10.0.26100.33296

Details and references

CVSS 3.1: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity from: the vendor (its own CVE record or advisory)
Weakness: CWE-362, CWE-416

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