Heap-based buffer overflow in Microsoft products - CVE-2026-55127
Published: July 17, 2026
Vulnerability identifier: #VU138216
CSH Severity: High
CVSS v4.0: 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/E:U/U:Amber
CVE-ID: CVE-2026-55127
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Microsoft
Affected software:
Microsoft Office for macOS
Microsoft Word
Microsoft SharePoint Server
Microsoft Office for macOS
Microsoft Word
Microsoft SharePoint Server
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to heap-based buffer overflow in Microsoft Word when parsing a crafted Office file. A remote attacker can send a specially crafted Office file to execute arbitrary code.
User interaction is required to open or preview the crafted file, and the Preview Pane is an attack vector.
How to mitigate CVE-2026-55127
Install security update from vendor's website.