Heap-Based Buffer Overflow in Microsoft Office Word by Microsoft
CVE-2026-63518

7.8HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft 365 Apps For Enterprise
Microsoft Office 2019
Microsoft Office 365 For Mac
Microsoft Office Ltsc 2021
Vendor
CVE Published:
11 August 2026

What is CVE-2026-63518?

A heap-based buffer overflow vulnerability in Microsoft Office Word has been identified, which could allow an unauthorized attacker to execute arbitrary code locally. This vulnerability arises from improper handling of objects in memory, enabling potential exploitation to manipulate system-level processes. Users are advised to apply available security updates to mitigate risks associated with this vulnerability and enhance the security posture of their systems.

Affected Version(s)

Microsoft 365 Apps for Enterprise 32-bit Systems 16.0.1

Microsoft Office 2019 32-bit Systems 19.0.0

Microsoft Office 365 for Mac 1.0.0 < 16.112.26081010

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

.