CVE-2026-70318

Analyzed Analyzed - Analysis Complete

Improper Input Validation in Microsoft Office Excel

Publication date: 2026-08-11

Last updated on: 2026-08-12

Assigner: Microsoft Corporation

Description

Improper input validation in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-11

Last Modified

2026-08-12

Generated

2026-09-01

AI Q&A

2026-08-11

EPSS Evaluated

2026-08-30

NVD

CVE-2026-70318

EUVD

EUVD-2026-56574

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	365_apps	*
microsoft	365_apps	*
microsoft	word	2016
microsoft	word	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-20	The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

Attack-Flow Graph

Executive Summary

This vulnerability is an improper input validation flaw in Microsoft Office Excel that allows an unauthorized attacker to disclose information locally. It does not require user interaction beyond normal use and has a base severity score of 5.5.

Detection Guidance

Detection of this vulnerability requires checking for improper input validation in Microsoft Office Excel. Since this is a local information disclosure issue, monitor for suspicious Excel file processing or unexpected data exposure. Ensure Excel is updated to the latest version to mitigate risks.

Impact Analysis

An attacker could exploit this to access sensitive information stored in Excel files on your local system. The impact is limited to local disclosure and does not allow code execution or system compromise.

Compliance Impact

This vulnerability allows local information disclosure due to improper input validation in Microsoft Office Excel. It may impact compliance by potentially exposing sensitive data, which could violate GDPR's data protection requirements or HIPAA's safeguards for protected health information if such data is involved.

Mitigation Strategies

Apply the latest security updates from Microsoft for Office Excel to address the improper input validation issue. Monitor Microsoft's official security advisories for patches and follow their recommended mitigation steps.

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