CVE-2026-85858: CWE-125: Out-of-bounds Read in Microsoft Windows 11 version 23H2
Description
CVE-2026-85858 is an out-of-bounds read vulnerability in the Windows Win32 Kernel Subsystem affecting Windows 11 version 23H2. It allows an authorized local attacker to elevate privileges. The vulnerability has a high severity with a CVSS score of 7.8. Microsoft has released an official fix for this issue.
CVSS v3.1
Score 7.8high
Affected software
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 (CVE-2026-85858) involves an out-of-bounds read in the Windows Win32 Kernel Subsystem in Windows 11 version 23H2. An authorized attacker with local access can exploit this flaw to elevate privileges. The CVSS 3.1 vector indicates the attack requires local access with high attack complexity and low privileges, no user interaction, and results in high impact to confidentiality, integrity, and availability. Microsoft has published an official fix addressing this vulnerability.
Potential Impact
Successful exploitation allows an authorized local attacker to elevate privileges, potentially gaining higher system rights. The vulnerability impacts confidentiality, integrity, and availability at a high level. 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 updates provided by Microsoft as detailed in the vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85858 to remediate this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-09-04T18:15:10.738Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85858","vendor":"Microsoft"}]
Threat ID: 6ace85462cdf04f6569fec50
Added to database: 10/13/2026, 19:23:50 UTC
Last enriched: 10/14/2026, 03:04:45 UTC
Last updated: 10/14/2026, 03:04:45 UTC
Views: 2
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