CVE intelligence

CVE-2026-40359

Vulnerability intelligence

Published May 12, 2026Sources checked Nov 11, 2026

7.8HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-40359 and is rated High severity with a CVSS score of 7.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: May 12, 2026

Vendor remediation details

Click to Run Release Notes Install KB5002871. Install KB5002865.

Vendor-listed releases

16.0.10417.20128
https://aka.ms/OfficeSecurityReleases
16.109.26051019
16.0.5552.1000

CISA KEVNot listedBased on the latest collected catalog

EPSS0.3%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-40359?

Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

Source: NVD