This vulnerability (CVE-2026-20946) involves an out-of-bounds read in Microsoft Office Excel, part of Microsoft 365 Apps for Enterprise. It allows an unauthorized attacker to execute code locally on the affected system. The CVSS 3.1 base score is 7.8, indicating high severity, with attack vector local, low attack complexity, no privileges required, user interaction required, unchanged scope, and high impact on confidentiality, integrity, and availability. Microsoft has published an official fix and manages remediation for this cloud service. The affected version explicitly stated is 16.0.1.

Successful exploitation could lead to local code execution by an unauthorized attacker, potentially compromising confidentiality, integrity, and availability of the affected system. The vulnerability requires local access and user interaction to exploit.

An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages remediation server-side. Users and administrators should apply the official update as directed in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20946 to remediate this vulnerability.