Heap-based Buffer Overflow in Microsoft Office Excel
CVE-2026-81389

7HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft 365 Apps For Enterprise
Microsoft Excel 2016
Microsoft Office 2016
Microsoft Office 2019
Vendor
CVE Published:
8 September 2026

What is CVE-2026-81389?

A heap-based buffer overflow vulnerability in Microsoft Office Excel could allow an unauthorized attacker to execute arbitrary code on the local system. This exploitation may occur through specially crafted documents, leading to security breaches and potential data loss. Users are advised to apply the necessary updates to mitigate this risk.

Affected Version(s)

Microsoft 365 Apps for Enterprise 32-bit Systems 16.0.1 < 16.0.20326.20138

Microsoft Excel 2016 32-bit Systems 16.0.0.0 < 16.0.5569.1003

Microsoft Office 2016 32-bit Systems 16.0.0 < 16.0.5569.1003

References

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

CVSS V3.1

Score:
7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
High
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.