CVE-2026-64904

Analyzed Analyzed - Analysis Complete

Type Confusion in Microsoft Office Enables Local Code Execution

Publication date: 2026-08-11

Last updated on: 2026-08-14

Assigner: Microsoft Corporation

Description

Access of resource using incompatible type ('type confusion') in Microsoft Office allows an unauthorized attacker to execute code locally.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-11

Last Modified

2026-08-14

Generated

2026-08-31

AI Q&A

2026-08-12

EPSS Evaluated

2026-08-30

NVD

CVE-2026-64904

EUVD

EUVD-2026-56707

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	365_apps	*
microsoft	365_apps	*
microsoft	office_2019	*
microsoft	office_2019	*
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-843	The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

Attack-Flow Graph

Executive Summary

This vulnerability is a type confusion flaw in Microsoft Office. It occurs when the software incorrectly handles data types, allowing an attacker to execute arbitrary code on a local system. The attacker does not need special privileges but requires user interaction to trigger the issue.

Detection Guidance

Detection typically involves checking for unusual behavior in Microsoft Office applications or monitoring for known indicators of compromise. Use Microsoft Defender for Office 365 to scan for suspicious activity. Check for updates from Microsoft to ensure the latest patches are applied.

Impact Analysis

An attacker could exploit this to run malicious code on your computer, potentially stealing data, installing malware, or taking control of your system. Since it requires user interaction, opening a specially crafted file could trigger the attack.

Compliance Impact

This vulnerability allows unauthorized code execution, which could lead to data breaches or unauthorized access to sensitive information. Such breaches may violate compliance requirements under GDPR, HIPAA, or other regulations depending on the data involved.

Mitigation Strategies

Apply the latest security updates from Microsoft for Office products as soon as they become available. Monitor the Microsoft Security Response Center for patches and advisories related to CVE-2026-64904.

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