Heap-Based Buffer Overflow in Microsoft Office Excel by Microsoft
CVE-2026-118726

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-2026-118726?

A heap-based buffer overflow vulnerability in Microsoft Office Excel enables unauthorized attackers to execute arbitrary code through specially crafted content delivered over a network. This security flaw could lead to significant data exposure and compromise system integrity if exploited.

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

.