Integer underflow in Microsoft products - CVE-2026-44820
Published: June 10, 2026
Vulnerability identifier: #VU134208
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-2026-44820
CWE-ID: CWE-191
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 integer underflow in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file, trigger integer underflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Affected software
Office Online Server
Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft Excel
Microsoft Office LTSC
Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft Excel
Microsoft Office LTSC
How to mitigate CVE-2026-44820
Install updates from vendor's website.