CVE-2026-66802CriticalRevised 20 Aug
Windows Device Health Attestation (DHA) Remote Code Execution Vulnerability
Assessment
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.
- Severity
- Critical
- CVSS base score
- 8.1CVSS:3.1/
AV:N/ AC:H/ PR:N/ UI:N/ S:U/ C:H/ I:H/ A:H/ E:U/ RL:O/ RC:C - Impact
- Remote Code Execution
- EPSS, next 30 days
- 0.5%Higher than 43.3% of scored CVEs · FIRST model run 26 Sep 2026 · about EPSS
- Exploitability
- Exploitation Less Likely
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- Windows Device Health Attestation (DHA)
- Weakness
- CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
- Issued by
- Microsoft
- Published
- 11 Aug 2026 · August 2026
- Last revised
- 20 Aug 2026Corrected the Executive Summary to clarify that the vulnerability affects Windows Device Health Attestation (DHA), not Microsoft Azure Attestation. This is an informational change only.
Updates that fix it
6 KBs| KB | Type | Restart | Applies to | Other CVEs |
|---|---|---|---|---|
| KB5120228 | Security Hotpatch Update | Required | Windows Server 2025, Windows Server 2025 (Server Core installation) | All CVEs in KB5120228 |
| KB5120229 | Security Hotpatch Update | Required | Windows Server 2022, Windows Server 2022 (Server Core installation) | All CVEs in KB5120229 |
| KB5120233 | Security Update | Required | Windows Server 2025, Windows Server 2025 (Server Core installation) | All CVEs in KB5120233 |
| KB5120238 | Security Update | Required | Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows Server 2019 and 1 more | All CVEs in KB5120238 |
| KB5120242 | Security Update | Required | Windows Server 2022, Windows Server 2022 (Server Core installation) | All CVEs in KB5120242 |
| KB5121000 | Security Update | Required | Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems | All CVEs in KB5121000 |
Affected products
Windows10 affected products
- Windows 10 Version 1809 for 32-bit Systems
- Windows 10 Version 1809 for x64-based Systems
- Windows 11 Version 26H1 for ARM64-based Systems
- Windows 11 version 26H1 for x64-based Systems
- Windows Server 2019
- Windows Server 2019 (Server Core installation)
- Windows Server 2022
- Windows Server 2022 (Server Core installation)
- Windows Server 2025
- Windows Server 2025 (Server Core installation)