Summary
Impact: Remote Code Execution. Microsoft rating: Critical. Not known to be exploited — Exploitation More Likely. Customer action: Required.
Details
Is the Preview Pane an attack vector for this vulnerability?
Yes, the Preview Pane is an attack vector.
According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?
The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally.
For example, when the score indicates that the Attack Vector is Local and User Interaction is Required, this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and open a specially crafted file from a website which leads to a local attack on their computer.
Security updates
https — https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
16.109.26051019 — https://go.microsoft.com/fwlink/p/?linkid=831049
16.0.5552.1000 — https://support.microsoft.com/help/5002858
Vulnerabilities 1
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High 8.4
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.
Revision history
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#1
Information published.
References
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CVE-2026-40364 Microsoft Word Remote Code Execution Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40364
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss