CVE-2026-66802: Windows Device Health Attestation (DHA) Remote Code Execution Vulnerability

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-11 · updated 2026-10-30
Weakness: CWE-362

Description

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 products

Microsoft Windows 10: before 10.0.17763.9121 — fixed in 10.0.17763.9121
Microsoft Windows 11 version 26H1: before 10.0.28000.2704 — fixed in 10.0.28000.2704
Microsoft Windows Server 2019: before 10.0.17763.9121 — fixed in 10.0.17763.9121
Microsoft Windows Server 2022: before 10.0.20348.5440 — fixed in 10.0.20348.5440
Microsoft Windows Server 2025: before 10.0.26100.33222 — fixed in 10.0.26100.33222
Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.9121 — fixed in 10.0.17763.9121
Microsoft Windows 11 version 26H1: from 10.0.28000.0 before 10.0.28000.2704 — fixed in 10.0.28000.2704
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.9121 — fixed in 10.0.17763.9121
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.5499 — fixed in 10.0.20348.5499
Microsoft Windows Server 2025: from 10.0.26100.0 before 10.0.26100.33296 — fixed in 10.0.26100.33296

How to fix

Upgrade to a fixed version: Microsoft Windows 10 10.0.17763.9121; Microsoft Windows 11 version 26H1 10.0.28000.2704; Microsoft Windows Server 2019 10.0.17763.9121; Microsoft Windows Server 2022 10.0.20348.5440; Microsoft Windows Server 2025 10.0.26100.33222; Microsoft Windows 10 10.0.17763.9121; Microsoft Windows 11 version 26H1 10.0.28000.2704; Microsoft Windows Server 2019 10.0.17763.9121; Microsoft Windows Server 2022 10.0.20348.5499; Microsoft Windows Server 2025 10.0.26100.33296. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66802

Get alerted when CVE-2026-66802 or the next vulnerability affects your stack