Heap-based buffer overflow in Microsoft Word and Microsoft SharePoint Server - CVE-2026-55130
Published: July 17, 2026
Vulnerability identifier: #VU138239
CSH Severity: High
CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-55130
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to heap-based buffer overflow in Microsoft Office Word when parsing a specially crafted document. A remote attacker can trick the victim into opening a specially crafted file to execute arbitrary code.
User interaction is required to open a crafted file.
Affected software
Microsoft Word
Microsoft SharePoint Server
Microsoft SharePoint Server
How to mitigate CVE-2026-55130
Install security update from vendor's website.
Microsoft Word - update to 16.0.5561.1000
Microsoft SharePoint Server - addressed in versions 16.0.5561.1001, 16.0.10417.20175, 16.0.19725.20434
Microsoft SharePoint Server - addressed in versions 16.0.5561.1001, 16.0.10417.20175, 16.0.19725.20434