CVE-2026-21255: CWE-284: Improper Access Control in Microsoft Windows 10 Version 1607
Improper access control in Windows Hyper-V allows an authorized attacker to bypass a security feature locally.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-21255) affects Windows 10 Version 1607 (build 10.0.14393.0) and is categorized under CWE-284 (Improper Access Control). It allows a local attacker with some privileges to bypass security controls in the Windows Hyper-V virtualization platform, resulting in a complete impact on confidentiality, integrity, and availability. The CVSS v3.1 base score is 8.8, reflecting high severity with local attack vector, low attack complexity, and no user interaction required. Microsoft has released an official patch to remediate this vulnerability.
Potential Impact
Successful exploitation enables an authorized local attacker to bypass security features in Windows Hyper-V, potentially leading to full compromise of the affected system's confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the security update provided in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21255 to remediate this vulnerability.
CVE-2026-21255: CWE-284: Improper Access Control in Microsoft Windows 10 Version 1607
Description
Improper access control in Windows Hyper-V allows an authorized attacker to bypass a security feature locally.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-21255) affects Windows 10 Version 1607 (build 10.0.14393.0) and is categorized under CWE-284 (Improper Access Control). It allows a local attacker with some privileges to bypass security controls in the Windows Hyper-V virtualization platform, resulting in a complete impact on confidentiality, integrity, and availability. The CVSS v3.1 base score is 8.8, reflecting high severity with local attack vector, low attack complexity, and no user interaction required. Microsoft has released an official patch to remediate this vulnerability.
Potential Impact
Successful exploitation enables an authorized local attacker to bypass security features in Windows Hyper-V, potentially leading to full compromise of the affected system's confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the security update provided in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21255 to remediate this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2025-12-11T21:02:05.736Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21255","vendor":"Microsoft"}]
Threat ID: 698b76004b57a58fa120a039
Added to database: 2/10/2026, 6:16:32 PM
Last enriched: 5/12/2026, 5:13:11 AM
Last updated: 5/21/2026, 5:04:32 PM
Views: 108
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