This vulnerability, identified as CVE-2026-55031 and classified under CWE-125 (Out-of-bounds Read), affects Microsoft Office Excel in Microsoft 365 Apps for Enterprise. It allows an unauthorized attacker to perform an out-of-bounds read that can lead to local code execution. The CVSS 3.1 base score is 7.8, indicating high severity, with attack vector local, low attack complexity, no privileges required, and user interaction required. The vulnerability impacts confidentiality, integrity, and availability with high impact. Microsoft has published an official fix and manages remediation for this cloud service. The affected version explicitly stated is 16.0.1.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code locally, potentially leading to full compromise of the affected system's confidentiality, integrity, and availability. The vulnerability requires local access and user interaction, but no privileges are needed to initiate the attack.

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-2026-55031 to ensure protection against this vulnerability.