CVE-2026-83565

Analyzed Analyzed - Analysis Complete

Buffer Over-Read in Windows Encrypting File System

Publication date: 2026-10-13

Last updated on: 2026-10-28

Assigner: Microsoft Corporation

Description

Buffer over-read in Windows Encrypting File System (EFS) allows an authorized attacker to disclose information locally.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-10-13

Last Modified

2026-10-28

Generated

2026-11-08

AI Q&A

2026-10-14

EPSS Evaluated

2026-11-07

NVD

CVE-2026-83565

EUVD

EUVD-2026-99915

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_10_1607	to 10.0.14393.9612 (exc)
microsoft	windows_10_1607	to 10.0.14393.9612 (exc)
microsoft	windows_10_1809	to 10.0.17763.9376 (exc)
microsoft	windows_10_1809	to 10.0.17763.9376 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7807 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7807 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7807 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7652 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7652 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9711 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9711 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9711 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9711 (exc)
microsoft	windows_11_26h1	to 10.0.28000.3231 (exc)
microsoft	windows_11_26h1	to 10.0.28000.3231 (exc)
microsoft	windows_11_26h2	to 10.0.26300.9711 (exc)
microsoft	windows_11_26h2	to 10.0.26300.9711 (exc)
microsoft	windows_server_2025	to 10.0.26100.33650 (exc)
microsoft	windows_server_2022	to 10.0.20348.5761 (exc)
microsoft	windows_server_2016	to 10.0.14393.9612 (exc)
microsoft	windows_server_2019	to 10.0.17763.9376 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7807 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7807 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7807 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-126	The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

Attack-Flow Graph

Executive Summary

This vulnerability is a buffer over-read in Windows Encrypting File System (EFS). It allows an authorized attacker to read beyond the intended buffer memory, potentially disclosing sensitive information stored locally on the system.

Detection Guidance

This vulnerability is a local information disclosure issue in Windows EFS. Detection primarily involves monitoring for unusual file access patterns or unauthorized information exposure. Use Windows Event Viewer to check for EFS-related errors under Applications and Services Logs. Review system logs for unexpected file decryption events. No specific commands are provided in the available resources for direct detection.

Impact Analysis

An attacker with local access could exploit this to read sensitive data, such as encrypted files or credentials, that should normally be protected by EFS. This could lead to unauthorized data disclosure or further attacks.

Compliance Impact

This vulnerability could violate compliance requirements that mandate protection of sensitive data, such as GDPR (data confidentiality) or HIPAA (protected health information). Unauthorized data disclosure may result in legal penalties or reputational damage.

Mitigation Strategies

Apply the latest Windows security updates from Microsoft to patch the EFS buffer over-read vulnerability. Disable EFS if not required and monitor for unusual file access patterns.

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EPSS Chart

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