Integer Underflow Vulnerability in Microsoft Office Excel by Microsoft
CVE-2026-44820

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-2026-44820?

An integer underflow vulnerability in Microsoft Office Excel allows attackers to exploit the software and execute arbitrary code. This security flaw can occur when the software improperly handles integer operations, leading to potential unauthorized actions on affected systems. Users are advised to apply the latest security updates to mitigate risks associated with this vulnerability.

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

.