CVE-2026-40366

Name: CVE-2026-40366
Creator: NVD / NIST
Published: 2026-05-12T18:17:15.61+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.4/10EPSS 0.38%

Last modified Jun 17, 2026

CVE-2026-40366 is a high-severity vulnerability rated 8.4/10 on the CVSS scale. Access of resource using incompatible type ('type confusion') in Microsoft Office Word allows an unauthorized attacker to execute code locally.. EPSS estimates a 0.38% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

8.4/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.38%

30.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-416

Affected Software

Vendor	Product	Versions
Microsoft	365 Apps	All versions
Microsoft	Office	2019
Microsoft	Office Long Term Servicing Channel	2021
Microsoft	Office Long Term Servicing Channel	2024
Microsoft	Word	2016

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40366Vendor Advisory

Timeline

Published: May 12, 2026
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2026-40366?

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

How severe is CVE-2026-40366?

CVE-2026-40366 has a CVSS score of 8.4/10 (HIGH severity). The EPSS model estimates a 0.38% probability of exploitation in the next 30 days.

How do I fix CVE-2026-40366?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-40366?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST