Heap-based Buffer Overflow in Microsoft Office Word by Microsoft
CVE-2026-66810

5.5MEDIUM

Key Information:

Vendor

Microsoft
Status
Microsoft 365 Apps For Enterprise
Microsoft Office 2019
Microsoft Office 365 For Mac
Microsoft Office Ltsc 2021
Vendor
CVE Published:
11 August 2026

What is CVE-2026-66810?

A heap-based buffer overflow vulnerability in Microsoft Office Word allows unauthorized attackers to exploit the software, potentially leading to information disclosure. This flaw enables attackers to gain access to sensitive data stored locally, increasing the risk of data breaches. Users are advised to apply security patches provided by Microsoft to mitigate this risk.

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 365 for Mac 1.0.0 < 16.112.26081010

References

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

CVSS V3.1

Score:
5.5
Severity:
MEDIUM
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.