Remote Code Execution Vulnerability in Microsoft Office Word
CVE-2026-40366

8.4HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft 365 Apps For Enterprise
Microsoft Office 2019
Microsoft Office Ltsc 2021
Microsoft Office Ltsc 2024
Vendor
CVE Published:
12 May 2026

What is CVE-2026-40366?

A use after free vulnerability in Microsoft Office Word allows an unauthorized attacker to execute arbitrary code locally on an affected system. This can lead to unauthorized access and potentially compromise the data integrity of the user’s machine. It highlights the importance of applying security updates promptly to mitigate risks associated with this vulnerability.

Affected Version(s)

Microsoft 365 Apps for Enterprise 32-bit Systems 16.0.1

Microsoft Office 2019 32-bit Systems 19.0.0

Microsoft Office LTSC 2021 32-bit Systems 16.0.1

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
8.4
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.