CVE-2026-83649

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Out-of-Bounds Read in Windows LSASS

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: Microsoft Corporation

Description

Out-of-bounds read in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to deny service over a network.

CVSS Scores

EPSS Scores

Probability:
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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-2026-83649

EUVD

EUVD-2026-99313

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 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-125	The product reads data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

Executive Summary

This vulnerability is an out-of-bounds read flaw in the Windows Local Security Authority Subsystem Service (LSASS). It allows an authorized attacker to cause a denial of service over a network by exploiting this memory access issue.

Impact Analysis

An attacker could exploit this to disrupt services on affected Windows systems, leading to system crashes or unresponsiveness. This could impact network availability and user access to critical services.

Compliance Impact

This vulnerability allows an authorized attacker to cause a denial of service via an out-of-bounds read in LSASS. Such disruptions could impact systems handling sensitive data, potentially violating compliance requirements for availability in standards like GDPR and HIPAA.

Mitigation Strategies

Apply the latest security updates from Microsoft to patch the out-of-bounds read vulnerability in LSASS. Monitor Microsoft's update guide for the specific patch and ensure all affected Windows versions are updated.

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