Heap-based buffer overflow in Microsoft products - CVE-2026-118715
Published: November 11, 2026
Vulnerability identifier: #VU165120
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-2026-118715
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to gain the privileges of the user account or service account running the affected process.
The vulnerability exists due to a heap-based buffer overflow in Microsoft Office Excel when processing a malicious Office file. A remote attacker can send a specially crafted Office file and convince a user to open it to gain the privileges of the account running the affected process.
The Preview Pane is not an attack vector for this vulnerability.
Affected software
Microsoft Office for macOS
Microsoft Office
Office Online Server
Microsoft Office
Office Online Server
How to mitigate CVE-2026-118715
Install security update from vendor's website.
Microsoft Office for macOS - update to 16.115.26110837
Office Online Server - update to 16.0.10417.20236
Microsoft Office - addressed in versions 16.0.14334.21048, 16.0.17932.21140
Office Online Server - update to 16.0.10417.20236
Microsoft Office - addressed in versions 16.0.14334.21048, 16.0.17932.21140