CVE-2026-55122

Analyzed Analyzed - Analysis Complete

Microsoft Office Excel Out-of-Bounds Read Vulnerability

Publication date: 2026-07-14

Last updated on: 2026-07-15

Assigner: Microsoft Corporation

Description

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-07-14

Last Modified

2026-07-15

Generated

2026-08-04

AI Q&A

2026-07-15

EPSS Evaluated

2026-08-02

NVD

CVE-2026-55122

EUVD

EUVD-2026-44204

Affected Vendors & Products

Vendor	Product	Version / Range
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	*
microsoft	office_online_server	to 16.0.10417.20175 (exc)

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 out-of-bounds read in Microsoft Office Excel. It allows an unauthorized attacker to access and disclose information stored locally on a system where Excel is running.

Detection Guidance

This vulnerability is an out-of-bounds read in Microsoft Office Excel that allows local information disclosure. Detection typically involves checking for unusual Excel file behavior or crashes. Use Microsoft's official tools like the Microsoft Safety Scanner or Windows Defender Offline Scan to detect malicious files or exploits. Monitor system logs for Excel-related errors or unexpected processes.

Impact Analysis

An attacker could exploit this to read sensitive data from your system, such as files or memory contents, potentially leading to unauthorized information disclosure.

Compliance Impact

This vulnerability could lead to unauthorized data exposure, which may violate compliance requirements under GDPR, HIPAA, or other regulations that mandate protection of sensitive information.

Mitigation Strategies

Apply the latest security updates from Microsoft for Office Excel as soon as they become available to patch the out-of-bounds read vulnerability.

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