CVE-2026-81391

Analyzed Analyzed - Analysis Complete

Use of Uninitialized Resource in Microsoft Office Excel Allows Information Disclosure

Publication date: 2026-09-08

Last updated on: 2026-09-09

Assigner: Microsoft Corporation

Description

Use of uninitialized resource in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-09-08

Last Modified

2026-09-09

Generated

2026-09-29

AI Q&A

2026-09-10

EPSS Evaluated

2026-09-27

NVD

CVE-2026-81391

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	365_apps	*
microsoft	365_apps	*
microsoft	excel	2016
microsoft	excel	2016
microsoft	office_2019	*
microsoft	office_2019	*
microsoft	office_2016	*
microsoft	office_2016	*
microsoft	microsoft_365	*
microsoft	office_2021	*
microsoft	office_2021	*
microsoft	office_2021	*
microsoft	office_2024	*
microsoft	office_2024	*
microsoft	office_2024	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-908	The product uses or accesses a resource that has not been initialized.

Attack-Flow Graph

Executive Summary

This vulnerability involves Microsoft Office Excel using an uninitialized resource, which allows an unauthorized attacker to access and disclose information stored locally on a system.

Impact Analysis

An attacker could exploit this to read sensitive data stored on your device, such as files opened in Excel, potentially leading to unauthorized information disclosure.

Compliance Impact

This vulnerability could lead to unauthorized data exposure, which may violate GDPR (data protection) or HIPAA (health information privacy) if sensitive data is accessed.

Mitigation Strategies

Apply the latest security updates from Microsoft to address the uninitialized resource issue in Excel. Monitor Microsoft's official update guide for patches and install them promptly.

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