Heap-based Buffer Overflow in Microsoft Office Excel
CVE-2026-81959

7.8HIGH

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-2026-81959?

A heap-based buffer overflow in Microsoft Office Excel poses a significant security risk allowing unauthorized attackers to execute arbitrary code on affected systems. This vulnerability can be exploited by tricking users into opening a specially crafted file. Users are advised to apply the latest security updates to mitigate potential threats.

Affected Version(s)

Microsoft 365 Apps for Enterprise 32-bit Systems 16.0.1 < 16.0.20326.20140

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:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.