Heap-based buffer overflow in Microsoft products - CVE-2026-26108
Published: March 11, 2026
Vulnerability identifier: #VU123799
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-2026-26108
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 on the target system.
The vulnerability exists due to a boundary error in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file, trigger a heap-based buffer overflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Affected software
Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft Excel
Microsoft Office LTSC
Office Online Server
Microsoft Office
Microsoft Excel
Microsoft Office LTSC
Office Online Server
How to mitigate CVE-2026-26108
Install updates from vendor's website.
Microsoft Excel - update to 16.0.5543.1000
Office Online Server - update to 16.0.10417.20102
Office Online Server - update to 16.0.10417.20102