Use After Free Vulnerability in Microsoft Office Excel
CVE-2026-40359

7.8HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft 365 Apps For Enterprise
Microsoft Excel 2016
Microsoft Office 2019
Microsoft Office Ltsc 2021
Vendor
CVE Published:
12 May 2026

What is CVE-2026-40359?

A use after free vulnerability in Microsoft Office Excel could allow an unauthorized attacker to execute arbitrary code on the user's machine. This exploitation occurs when a program attempts to access memory after it has been freed, potentially leading to a system compromise. It is crucial for users to apply the latest updates and security patches to mitigate this risk.

Affected Version(s)

Microsoft 365 Apps for Enterprise 32-bit Systems 16.0.1

Microsoft Excel 2016 32-bit Systems 16.0.0.0 < 16.0.5552.1000

Microsoft Office 2019 32-bit Systems 19.0.0

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.