Heap-Based Buffer Overflow in Microsoft Office by Microsoft
CVE-2026-55140

7.8HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft 365 Apps For Enterprise
Microsoft Office 2016
Microsoft Office 2019
Microsoft Office 365 For Mac
Vendor
CVE Published:
14 July 2026

What is CVE-2026-55140?

A heap-based buffer overflow vulnerability exists in Microsoft Office that could allow an unauthorized attacker to execute arbitrary code locally. This type of vulnerability can be exploited to manipulate memory, leading to potential unauthorized access or execution of malicious commands on affected systems. Users are advised to apply the latest updates to mitigate this risk.

Affected Version(s)

Microsoft 365 Apps for Enterprise 32-bit Systems 16.0.1

Microsoft Office 2016 32-bit Systems 16.0.0 < 16.0.5561.1000

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

.