Integer Underflow in Microsoft Office Excel Leads to Code Execution

Publication date: 2026-06-09

Last updated on: 2026-06-19

Assigner: Microsoft Corporation

Description

Integer underflow (wrap or wraparound) in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-06-09

Last Modified

2026-06-19

Generated

2026-06-30

AI Q&A

2026-06-09

EPSS Evaluated

2026-06-28

NVD

CVE-2026-44817

EUVD

EUVD-2026-35660

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	office_online_server	*
microsoft	365_apps	*
microsoft	365_apps	*
microsoft	excel	2016
microsoft	excel	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-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 an integer underflow (wrap or wraparound) issue in Microsoft Office Excel. It allows an unauthorized attacker to execute code locally on the affected system.

Impact Analysis

The vulnerability can lead to local code execution by an unauthorized attacker, which means the attacker could run malicious code on your system with potentially high impact on confidentiality, integrity, and availability.

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