Integer Underflow Vulnerability in Microsoft Office Excel
CVE-2026-44818

7HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft 365 Apps For Enterprise
Microsoft Excel 2016
Microsoft Office 2019
Microsoft Office 365 For Mac
Vendor
CVE Published:
9 June 2026

What is CVE-2026-44818?

An integer underflow vulnerability exists in Microsoft Office Excel, which can be exploited by an unauthorized attacker to trigger code execution on the local machine. This flaw can allow for malicious actions that may compromise the server or user data. Users are encouraged to update their Excel application to mitigate potential risks associated with this vulnerability. For more details and patch information, please refer to the Microsoft advisory.

Affected Version(s)

Microsoft 365 Apps for Enterprise 32-bit Systems 16.0.1

Microsoft Excel 2016 32-bit Systems 16.0.0.0 < 16.0.5556.1001

Microsoft Office 2019 32-bit Systems 19.0.0

References

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

CVSS V3.1

Score:
7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
High
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.