CVE-2026-78503

Analyzed Analyzed - Analysis Complete

Out-of-Bounds Read in Microsoft Office Word

Publication date: 2026-09-08

Last updated on: 2026-09-08

Assigner: Microsoft Corporation

Description

Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.

CVSS Scores

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Meta Information

Published

2026-09-08

Last Modified

2026-09-08

Generated

2026-09-29

AI Q&A

2026-09-09

EPSS Evaluated

2026-09-27

NVD

CVE-2026-78503

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

Attack-Flow Graph

Executive Summary

This is an out-of-bounds read vulnerability in Microsoft Office Word. It allows an unauthorized attacker to access memory outside the intended boundaries, potentially disclosing sensitive information over a network.

Impact Analysis

An attacker could exploit this to read sensitive data from your system, such as documents or personal information, without needing authentication. This could lead to data leaks or further attacks.

Compliance Impact

This vulnerability could result in unauthorized data exposure, violating GDPR's data protection principles or HIPAA's confidentiality requirements. Organizations may face compliance penalties if exploited.

Mitigation Strategies

Apply the latest security updates from Microsoft for affected Office Word versions immediately. Disable automatic opening of documents from untrusted sources and enable Protected View in Office settings.

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