Out-of-bounds Write in Microsoft Office

Publication date: 2026-09-08

Last updated on: 2026-09-09

Assigner: Microsoft Corporation

Description

Out-of-bounds write in Microsoft Office allows an unauthorized attacker to execute code over a network.

CVSS Scores

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Meta Information

Published

2026-09-08

Last Modified

2026-09-09

Generated

2026-09-30

AI Q&A

2026-09-09

EPSS Evaluated

2026-09-27

NVD

CVE-2026-78524

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	365_apps	*
microsoft	365_apps	*
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-787	The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

Executive Summary

This vulnerability is an out-of-bounds write in Microsoft Office that allows an unauthorized attacker to execute arbitrary code remotely over a network. It occurs when software writes data past the end of allocated memory buffers, potentially corrupting adjacent memory and enabling malicious code execution.

Impact Analysis

If exploited, this vulnerability could allow attackers to run malicious code on your system without authentication. This could lead to data theft, installation of malware, or unauthorized system access. Users are impacted if they open a specially crafted Office file from an untrusted source.

Mitigation Strategies

Apply the latest security updates from Microsoft for Office products as soon as possible to patch the out-of-bounds write vulnerability.

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