Buffer Overflow Vulnerability in Microsoft Office Excel
CVE-2026-118731

8.8HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft 365 Apps For Enterprise
Microsoft Office 365 For Mac
Microsoft Office Ltsc 2021
Microsoft Office Ltsc 2024
Vendor
CVE Published:
10 November 2026

What is CVE-2026-118731?

A stack-based buffer overflow vulnerability in Microsoft Office Excel could allow an attacker to execute arbitrary code on an affected system via a specially crafted file. This exploitation requires user interaction, as the victim must open a maliciously designed Excel file. Successful exploitation may compromise the confidentiality, integrity, and availability of the system.

Affected Version(s)

Microsoft 365 Apps for Enterprise 32-bit Systems 16.0.1

Microsoft Office 365 for Mac 1.0.0 < 16.115.26110837

Microsoft Office LTSC 2021 32-bit Systems 16.0.1 < 16.0.14334.21048

References

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

CVSS V3.1

Score:
8.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.