This vulnerability (CVE-2026-44818) involves a race condition (CWE-362) in Microsoft Office Excel as part of Microsoft 365 Apps for Enterprise. Improper synchronization when accessing shared resources during concurrent execution can be exploited by an unauthorized attacker to execute code locally. The CVSS v3.1 score is 7.0, indicating high severity, with attack vector local, high attack complexity, no privileges required, and user interaction required. Microsoft has published an official fix and manages remediation for this cloud-hosted service.

Successful exploitation allows an unauthorized attacker to execute code locally on the affected system, potentially leading to full compromise of confidentiality, integrity, and availability of the system. The vulnerability requires local access and user interaction, with high attack complexity.

An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages the 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-2026-44818 to mitigate this vulnerability.