CVE-2026-83666

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Race Condition in Active Directory Certificate Services Elevates Privileges

Publication date: 2026-10-13

Last updated on: 2026-10-14

Assigner: Microsoft Corporation

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Active Directory Certificate Services (AD CS) allows an authorized attacker to elevate privileges locally.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-13

Last Modified

2026-10-14

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-83666

EUVD

EUVD-2026-99320

Affected Vendors & Products

Vendor	Product	Version / Range
Microsoft	Windows	10 Version 1607 10.0.14393.0
Microsoft	Windows	10 Version 1809 10.0.17763.0
Microsoft	Windows	Server 2012 6.2.9200.0
Microsoft	Windows	Server 2012 (Server Core installation) 6.2.9200.0
Microsoft	Windows	Server 2012 R2 6.3.9600.0
Microsoft	Windows	Server 2012 R2 (Server Core installation) 6.3.9600.0
Microsoft	Windows	Server 2016 10.0.14393.0
Microsoft	Windows	Server 2016 (Server Core installation) 10.0.14393.0
Microsoft	Windows	Server 2019 10.0.17763.0
Microsoft	Windows	Server 2019 (Server Core installation) 10.0.17763.0
Microsoft	Windows	Server 2022 10.0.20348.0
Microsoft	Windows	Server 2025 10.0.26100.0
Microsoft	Windows	Server 2025 (Server Core installation) 10.0.26100.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
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 Active Directory Certificate Services (AD CS) where improper synchronization during concurrent execution allows an authorized attacker to elevate their privileges locally.

Impact Analysis

An attacker with local access could exploit this to gain higher privileges, potentially allowing them to take control of affected systems or access sensitive data.

Compliance Impact

This vulnerability allows local privilege escalation in Active Directory Certificate Services (AD CS), which could lead to unauthorized access to sensitive systems or data. For compliance standards like GDPR and HIPAA, such unauthorized access risks data breaches, potentially violating confidentiality and integrity requirements.

Mitigation Strategies

Apply the latest security updates from Microsoft for Active Directory Certificate Services (AD CS) to address the race condition vulnerability. Monitor Microsoft's security advisories for patches and follow their recommended mitigation steps.

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