This vulnerability, tracked as CVE-2026-44820 and categorized under CWE-125 (Out-of-bounds Read), affects Microsoft Office Excel within Microsoft 365 Apps for Enterprise. It allows an unauthorized attacker to perform a local code execution by exploiting an out-of-bounds read condition. The CVSS v3.1 base score is 7.8, indicating high severity, with attack vector local, low attack complexity, no privileges required, user interaction required, and impacts confidentiality, integrity, and availability. Microsoft has published an official fix and manages remediation for this cloud-hosted service. The affected version explicitly stated is 16.0.1.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code locally on the affected system, potentially leading to full compromise of confidentiality, integrity, and availability of the affected application environment. However, exploitation requires local access and user interaction.

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-2026-44820 to mitigate this vulnerability.