CVE-2026-63525

Analyzed Analyzed - Analysis Complete

Numeric Truncation Error in Microsoft Office Word Leads to Code Execution

Publication date: 2026-08-11

Last updated on: 2026-08-13

Assigner: Microsoft Corporation

Description

Numeric truncation error in Microsoft Office Word allows an unauthorized attacker to execute code locally.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-11

Last Modified

2026-08-13

Generated

2026-09-01

AI Q&A

2026-08-11

EPSS Evaluated

2026-08-30

NVD

CVE-2026-63525

EUVD

EUVD-2026-56691

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	365_apps	*
microsoft	365_apps	*
microsoft	word	2016
microsoft	word	2016
microsoft	office_2019	*
microsoft	office_2019	*
microsoft	office_2021	*
microsoft	office_2021	*
microsoft	office_2024	*
microsoft	office_2024	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-197	Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.

Attack-Flow Graph

Executive Summary

This vulnerability is a numeric truncation error in Microsoft Office Word that allows an unauthorized attacker to execute code locally on a victim's system.

Detection Guidance

This vulnerability involves a numeric truncation error in Microsoft Office Word enabling local code execution. Detection requires checking for unpatched Office installations or suspicious Word document processing. Monitor for unusual Word process behavior or unexpected network connections from Word.exe.

Impact Analysis

An attacker could exploit this flaw to run malicious code on your computer, potentially leading to unauthorized access, data theft, or further system compromise if you open a specially crafted document.

Compliance Impact

This vulnerability allows unauthorized code execution locally, which could lead to unauthorized access to sensitive data. This may impact compliance with GDPR (data protection) and HIPAA (health data privacy) by increasing the risk of data breaches or unauthorized processing.

Mitigation Strategies

Apply the latest security updates from Microsoft for Office Word as soon as possible to patch the numeric truncation error. Disable macros from untrusted sources and restrict user permissions to reduce attack surface.

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