CVE-2026-45487: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition in Microsoft Windows 10 Version 21H2
Time-of-check time-of-use (TOCTOU) race condition in Program Compatibility Assistant Service allows an authorized attacker to elevate privileges locally.
AI Analysis
Technical Summary
This vulnerability is a TOCTOU race condition (CWE-367) in the Program Compatibility Assistant Service of Windows 10 Version 21H2 (build 10.0.19044.0). It enables a local attacker with some level of authorization to exploit the timing window between checking and using a resource, resulting in privilege escalation. The CVSS 3.1 base score is 7.8, indicating high severity, with impact on confidentiality, integrity, and availability. Microsoft has published an official fix for this vulnerability.
Potential Impact
An authorized local attacker can exploit this race condition to elevate privileges, potentially gaining higher system rights than intended. This can lead to full system compromise, affecting confidentiality, integrity, and availability of the affected system.
Mitigation Recommendations
Microsoft has released an official fix for this vulnerability. Users and administrators should apply the security update provided by Microsoft for Windows 10 Version 21H2 (build 10.0.19044.0) as soon as possible to remediate this issue.
CVE-2026-45487: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition in Microsoft Windows 10 Version 21H2
Description
Time-of-check time-of-use (TOCTOU) race condition in Program Compatibility Assistant Service allows an authorized attacker to elevate privileges locally.
CVSS v3.1
Score 7.8high
Affected software
Microsoft
Windows 10 Version 21H2
Microsoft
Windows 10 Version 22H2
Microsoft
Windows 11 version 23H2
Microsoft
Windows 11 Version 23H2
Microsoft
Windows 11 Version 24H2
Microsoft
Windows 11 Version 25H2
Microsoft
Windows 11 version 26H1
Microsoft
Windows Server 2022
Microsoft
Windows Server 2025
Microsoft
Windows Server 2025 (Server Core installation)
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability is a TOCTOU race condition (CWE-367) in the Program Compatibility Assistant Service of Windows 10 Version 21H2 (build 10.0.19044.0). It enables a local attacker with some level of authorization to exploit the timing window between checking and using a resource, resulting in privilege escalation. The CVSS 3.1 base score is 7.8, indicating high severity, with impact on confidentiality, integrity, and availability. Microsoft has published an official fix for this vulnerability.
Potential Impact
An authorized local attacker can exploit this race condition to elevate privileges, potentially gaining higher system rights than intended. This can lead to full system compromise, affecting confidentiality, integrity, and availability of the affected system.
Mitigation Recommendations
Microsoft has released an official fix for this vulnerability. Users and administrators should apply the security update provided by Microsoft for Windows 10 Version 21H2 (build 10.0.19044.0) as soon as possible to remediate this issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-05-12T16:07:22.617Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45487","vendor":"Microsoft"}]
Threat ID: 6a284cdf8dd33fbd85664d97
Added to database: 06/09/2026, 17:26:55 UTC
Last enriched: 08/14/2026, 13:37:15 UTC
Last updated: 09/14/2026, 22:01:34 UTC
Views: 80
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