CVE-2026-66802

Modified Modified - Updated After Analysis

Race Condition in Microsoft Azure Attestation Service

Publication date: 2026-08-11

Last updated on: 2026-08-20

Assigner: Microsoft Corporation

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-11

Last Modified

2026-08-20

Generated

2026-08-31

AI Q&A

2026-08-11

EPSS Evaluated

2026-08-30

NVD

CVE-2026-66802

EUVD

EUVD-2026-56746

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_11_26h1	to 10.0.28000.2704 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2704 (exc)
microsoft	windows_server_2022	to 10.0.20348.5440 (exc)
microsoft	windows_server_2025	to 10.0.26100.33222 (exc)
microsoft	windows_10_1809	to 10.0.17763.9121 (exc)
microsoft	windows_10_1809	to 10.0.17763.9121 (exc)
microsoft	windows_server_2019	to 10.0.17763.9121 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
CWE-362	The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Attack-Flow Graph

Executive Summary

This is a race condition vulnerability in Microsoft Azure Attestation service and Device Health Attestation Service. It occurs when improper synchronization allows concurrent execution using shared resources. An unauthorized attacker can exploit this to execute code remotely over a network.

Detection Guidance

Detection of this race condition vulnerability requires monitoring for unusual concurrent access patterns in Microsoft Azure Attestation service and Device Health Attestation Service. Check for unexpected code execution events or unauthorized network activity targeting these services. Review logs for repeated failed authentication attempts or unusual process interactions between these services.

Impact Analysis

An attacker could gain control of affected services, leading to unauthorized code execution. This may allow data theft, service disruption, or further network compromise if the services are internet-facing or connected to critical systems.

Compliance Impact

This vulnerability could lead to unauthorized access or data breaches, violating confidentiality requirements in GDPR and HIPAA. Organizations using affected services may face compliance violations, fines, or legal consequences if proper remediation is not applied.

Mitigation Strategies

Apply the latest security updates from Microsoft for Azure Attestation service and Device Health Attestation Service as soon as possible to patch the race condition vulnerability.

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