Use After Free in Microsoft Windows 10 Version 1809
CVE-2026-66802
Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Azure Attestation service and Device Health Attestation Service allows an unauthorized attacker to execute code over a network.
Vulnerability class: Race Condition
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Microsoft Windows 10 Version 1809 — versions 10.0.17763.0
- Microsoft Windows 11 Version 26h1 — versions 10.0.28000.0
- Microsoft Windows Server 2019 — versions 10.0.17763.0
- Microsoft Windows Server 2019 (Server Core Installation) — versions 10.0.17763.0
- Microsoft Windows Server 2022 — versions 10.0.20348.0
- Microsoft Windows Server 2025 — versions 10.0.26100.0
- Microsoft Windows Server 2025 (Server Core Installation) — versions 10.0.26100.0
Weakness classification (CWE)
References
- Windows Device Health Attestation (DHA) Remote Code Execution Vulnerability (vendor-advisory, patch)
Frequently asked questions
- What is CVE-2026-66802?
- CVE-2026-66802 is a high-severity vulnerability in Microsoft Windows 10 Version 1809, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 8.1/10. Published 2026-08-11.
- How severe is CVE-2026-66802?
- High severity. CVSS v3 base score is 8.1 out of 10.