CVE-2026-70303

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Out-of-bounds Write in Windows Kernel

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: Microsoft Corporation

Description

Out-of-bounds write in Windows Kernel allows an authorized attacker to elevate privileges locally.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-10-13

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-70303

EUVD

EUVD-2026-99617

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	10 Version 21H2 10.0.19044.0
Microsoft	Windows	10 Version 22H2 10.0.19045.0
Microsoft	Windows	11 version 23H2 10.0.22631.0
Microsoft	Windows	11 Version 23H2 10.0.22631.0
Microsoft	Windows	11 Version 24H2 10.0.26100.0
Microsoft	Windows	11 Version 25H2 10.0.26200.0
Microsoft	Windows	11 version 26H1 10.0.28000.0
Microsoft	Windows	11 Version 26H2 10.0.26300.0
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-787	The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

Executive Summary

This is an out-of-bounds write vulnerability in the Windows Kernel. An authorized attacker with local access can exploit it to elevate their privileges on the system.

Detection Guidance

Detection requires checking for Windows kernel vulnerabilities. Use Windows Update to verify patch status. Run 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to check OS version. Check installed updates with 'wmic qfe list'. Enable Windows Defender Exploit Guard for runtime monitoring.

Impact Analysis

An attacker could gain higher-level permissions on your system, allowing them to install programs, view or delete data, or create new accounts with full user rights.

Compliance Impact

This vulnerability allows local privilege escalation in Windows systems, which could enable unauthorized access to sensitive data or system functions. This may impact compliance with GDPR (data protection) and HIPAA (health data security) by increasing risks of unauthorized data access or modification.

Mitigation Strategies

Apply the latest Windows security updates from Microsoft Update or the Microsoft Update Catalog to patch the Windows Kernel vulnerability. Monitor Microsoft's security advisories for additional guidance.

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