Integer overflow in Microsoft products - CVE-2026-55033
Published: July 17, 2026
Vulnerability identifier: #VU138212
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-2026-55033
CWE-ID: CWE-190
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 integer overflow or wraparound in Microsoft Word when parsing a crafted Office file. A remote attacker can send a specially crafted file to a user and convince them to open it to execute arbitrary code.
The Preview Pane is also an attack vector, and user interaction is required.
Affected software
Microsoft Office for macOS
Microsoft Word
Microsoft SharePoint Server
Microsoft Word
Microsoft SharePoint Server
How to mitigate CVE-2026-55033
Install security update from vendor's website.
Microsoft Office for macOS - update to 16.111.26071215
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 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