Integer overflow in Microsoft Office for macOS and Microsoft Office - CVE-2026-55057
Published: July 17, 2026
Vulnerability identifier: #VU138232
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-55057
CWE-ID: CWE-190
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to integer overflow or wraparound in Microsoft Office for macOS when parsing a crafted Office file. A remote attacker can send a specially crafted Office file to disclose sensitive information.
User interaction is required to open or preview the crafted file, and the Preview Pane is an attack vector. Successful exploitation could allow reading small portions of heap memory.
Affected software
Microsoft Office for macOS
Microsoft Office
Microsoft Office
How to mitigate CVE-2026-55057
Install security update from vendor's website.
Microsoft Office for macOS - update to 16.111.26071215
Microsoft Office - update to 16.0.5561.1000
Microsoft Office - update to 16.0.5561.1000