Use After Free Vulnerability in Microsoft Office Excel
CVE-2026-100209

8.8HIGH

Key Information:

Vendor

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

What is CVE-2026-100209?

A use after free vulnerability in Microsoft Office Excel may allow an unauthorized attacker to exploit the application to execute arbitrary code through crafted documents. This can potentially compromise the system and lead to unauthorized access to sensitive information. Users of affected versions are advised to apply security updates as soon as they are available to mitigate this risk.

Affected Version(s)

Microsoft 365 Apps for Enterprise 32-bit Systems 16.0.1

Microsoft Office 365 for Mac 1.0.0

Microsoft Office LTSC 2024 32-bit Systems 16.0.0 < 16.0.17932.21056

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

.