CVE-2026-44820

Analyzed Analyzed - Analysis Complete

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:
Percentile:

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-2026-44820

EUVD

EUVD-2026-35663

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

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.

Mitigation Strategies

To mitigate this vulnerability, apply the security updates provided by Microsoft for Microsoft Office Excel as soon as they become available.

Additionally, limit local access to affected systems and ensure that users do not open untrusted Excel files to reduce the risk of exploitation.

Impact Analysis

The vulnerability can lead to local code execution by an unauthorized attacker.

This means an attacker could potentially run malicious code on your system with the privileges of the user running Microsoft Excel.

The CVSS base score of 7.8 indicates a high severity impact affecting confidentiality, integrity, and availability.

Compliance Impact

The provided information does not specify how this vulnerability affects compliance with common standards and regulations such as GDPR or HIPAA.

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