Integer Underflow Vulnerability in Microsoft Excel by Microsoft
CVE-2026-44817

7.8HIGH

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-2026-44817?

An integer underflow issue in Microsoft Excel can allow an unauthorized attacker to manipulate memory and execute arbitrary code on an affected system. This vulnerability arises when calculated values exceed the allowable range, allowing an attacker to leverage this underflow condition for exploitative purposes. Users are strongly advised to apply the relevant patches to safeguard their systems against potential exploitation.

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:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.