This vulnerability is a stack-based buffer overflow (CWE-121) in Microsoft Office Access, part of Microsoft 365 Apps for Enterprise. It enables an unauthorized attacker to execute code locally, potentially leading to full compromise of confidentiality, integrity, and availability. The CVSS v3.1 score is 7.8, reflecting high impact with local attack vector, low attack complexity, no privileges required, and user interaction needed. Microsoft has published an official fix and manages remediation for this cloud service. The affected version explicitly identified is 16.0.1.

Successful exploitation allows local code execution by an unauthorized attacker, resulting in complete compromise of confidentiality, integrity, and availability of the affected system. This could lead to full control over the vulnerable Microsoft 365 Apps for Enterprise instance running Office Access.

An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages the remediation server-side. Users and administrators should follow the guidance in the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64919 to ensure their environment is updated and protected.