Heap-based buffer overflow in Microsoft products - CVE-2026-40362
Published: May 13, 2026
Vulnerability identifier: #VU131335
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-2026-40362
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Microsoft
Affected software:
Office Online Server
Microsoft 365 Apps for Enterprise
Microsoft Excel
Microsoft Office
Microsoft Office LTSC
Office Online Server
Microsoft 365 Apps for Enterprise
Microsoft Excel
Microsoft Office
Microsoft Office LTSC
Detailed vulnerability description
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.
How to mitigate CVE-2026-40362
Install updates from vendor's website.