CVE-2026-55054

Analyzed Analyzed - Analysis Complete

Out-of-bounds Read in Microsoft Office Excel

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 over a network.

CVSS Scores

EPSS Scores

Probability:
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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-2026-55054

EUVD

EUVD-2026-44197

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	office_2021	*
microsoft	office_2021	*
microsoft	office_2024	*
microsoft	office_2024	*
microsoft	office_2021	to 16.111.26071215 (exc)
microsoft	office_2024	to 16.111.26071215 (exc)
microsoft	office_online_server	to 16.0.10417.20175 (exc)
microsoft	office_365	to 16.111.26071215 (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 flaw in Microsoft Office Excel. It allows an unauthorized attacker to access and disclose sensitive information over a network by reading data beyond the intended memory boundaries.

Detection Guidance

This vulnerability involves an out-of-bounds read in Microsoft Office Excel, which may allow information disclosure. Detection typically requires checking for affected Microsoft Excel versions and applying Microsoft's security updates. Use Microsoft's official tools like Microsoft Defender for Office 365 to scan for vulnerable installations.

Impact Analysis

An attacker could exploit this to access sensitive data stored in Excel files, potentially leading to unauthorized information disclosure. Users should apply Microsoft's security updates to mitigate this risk.

Compliance Impact

This vulnerability could lead to unauthorized data exposure, violating GDPR's data protection principles or HIPAA's confidentiality requirements. Organizations must address it to maintain compliance.

Mitigation Strategies

Apply the latest security updates from Microsoft to patch the out-of-bounds read vulnerability in Excel. Monitor Microsoft's security advisories for updates and ensure all affected systems are updated promptly.

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