Heap-based Buffer Overflow in Microsoft Office Excel by Microsoft
CVE-2026-118718

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-2026-118718?

A heap-based buffer overflow vulnerability in Microsoft Office Excel allows unauthorized attackers to execute arbitrary code via a specially crafted document. This can be exploited over a network, posing significant security risks to users and organizations. It is essential for users to apply the latest patches to mitigate potential threats effectively. For detailed guidance, refer to Microsoft's advisory.

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

.