Microsoft Security Response CenterCVE-2026-40367

Microsoft Word Remote Code Execution Vulnerability

Access of resource using incompatible type ('type confusion') in Microsoft Office Word allows an unauthorized attacker to execute code locally.

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8.4CVSS out of 10Critical severity

Scope

What the vendor says is affected

Microsoft SharePoint Enterprise Server 2016
Microsoft SharePoint Server 2019
Microsoft Office 2019 for 32-bit editions
Microsoft Office 2019 for 64-bit editions
Microsoft 365 Apps for Enterprise for 32-bit Systems
Microsoft 365 Apps for Enterprise for 64-bit Systems
Microsoft Office LTSC for Mac 2021
Microsoft Office LTSC 2021 for 64-bit editions
Microsoft Office LTSC 2021 for 32-bit editions
Microsoft SharePoint Server Subscription Edition
Microsoft Office LTSC 2024 for 32-bit editions
Microsoft Office LTSC 2024 for 64-bit editions
Microsoft Office LTSC for Mac 2024
Microsoft Word 2016 (32-bit edition)
Microsoft Word 2016 (64-bit edition)

Versions the vendor lists as fixed

16.0.5552.1002
16.0.10417.20128
https://aka.ms/OfficeSecurityReleases
16.109.26051019
16.0.19725.20280
16.0.5552.1000

Next step

What the vendor recommends

Click to Run Release Notes Install KB5002868. Install KB5002869. Install KB5002870. Install KB5002872. Install KB5002863. Install KB5002858.

Review the complete instructions on the vendor's site

Timeline

When this advisory changed

May 12, 2026 at 7:00 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
May 20, 2026 at 7:00 AM UTC
Updated by Microsoft Security Response Center
The vendor changed the advisory after it was first published.
Sep 27, 2026 at 11:11 PM UTC
Added to SecurityAlert
We collected the advisory from the official source.

Vulnerabilities

CVEs named in this advisory

CVE-2026-40367View CVSS, KEV, EPSS, and threat context

Source

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Vendor: Microsoft Security Response Center
Advisory ID: CVE-2026-40367
Last source check: Sep 27, 2026 at 11:11 PM UTC

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What the vendor says is affected

Versions the vendor lists as fixed

What the vendor recommends

When this advisory changed

CVEs named in this advisory

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