This vulnerability involves an integer overflow or wraparound in Microsoft 365 Apps for Enterprise, specifically version 16.0.1. Successful exploitation could enable an unauthorized attacker to execute code locally on the affected system. The CVSS v3.1 base score is 7.8, indicating high severity with high impact on confidentiality, integrity, and availability. Microsoft has published an official fix and manages remediation for this cloud service. No active exploitation has been reported.

An attacker could leverage this integer overflow vulnerability to execute arbitrary code locally, potentially compromising confidentiality, integrity, and availability of the affected system. The impact is rated high due to the possibility of code execution without privileges and user interaction required.

Microsoft has released an official fix for this vulnerability. Users and administrators should apply the provided updates from Microsoft promptly. Since this is a cloud-hosted service, Microsoft manages remediation server-side. Refer to the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64903 for detailed patching instructions and confirmation of remediation status.