CVE-2026-96309: CWE-416: Use After Free in Microsoft Windows 10 Version 21H2
Description
Use after free in Windows Subsystem for Linux 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 11 Version 26H2
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, identified as CVE-2026-96309 and classified under CWE-416 (Use After Free), affects multiple builds of Microsoft Windows 10 Version 21H2. It occurs within the Windows Subsystem for Linux, where improper handling of memory can lead to use-after-free conditions. An authorized local attacker could exploit this flaw to elevate their privileges on the system. The CVSS v3.1 base score is 7.8, reflecting high impact on confidentiality, integrity, and availability. Microsoft has published an official advisory and provided patches to remediate the issue.
Potential Impact
Successful exploitation of this vulnerability allows an authorized local attacker to elevate privileges, potentially gaining higher-level access than intended. This can lead to full system compromise, including unauthorized access to sensitive data and disruption of system operations.
Mitigation Recommendations
An official fix is available from Microsoft. Users and administrators should apply the security updates provided by Microsoft as detailed in the vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96309. Applying these patches will remediate the vulnerability and prevent exploitation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-09-22T22:31:49.522Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96309","vendor":"Microsoft"}]
Threat ID: 6ace85772cdf04f656a0047a
Added to database: 10/13/2026, 19:24:39 UTC
Last enriched: 10/14/2026, 00:20:15 UTC
Last updated: 10/14/2026, 04:04:33 UTC
Views: 5
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