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HIGH · 8.4

CVE-2026-40366

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

Vulnerability Description

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

CVSS Score

8.4

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH

Affected Products

VendorProductVersions
Microsoft365 Apps-
MicrosoftOffice2019
MicrosoftOffice Long Term Servicing Channel2021
MicrosoftWord2016

Related Weaknesses (CWE)

CWE-416

References

FAQ

What is CVE-2026-40366?

CVE-2026-40366 is a vulnerability with a CVSS score of 8.4 (HIGH). Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally.

How severe is CVE-2026-40366?

CVE-2026-40366 has been rated HIGH with a CVSS base score of 8.4/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-40366?

Check the references section above for vendor advisories and patch information. Affected products include: Microsoft 365 Apps, Microsoft Office, Microsoft Office Long Term Servicing Channel, Microsoft Word.