This vulnerability (CVE-2026-55036) is a buffer over-read (CWE-126) in Microsoft Office Excel component of Microsoft 365 Apps for Enterprise. It allows an unauthorized attacker to execute code locally on the affected system. The CVSS 3.1 base score is 7.8, indicating high severity, with attack vector local, low attack complexity, no privileges required, user interaction required, and impacts to confidentiality, integrity, and availability. Microsoft has released an official fix and manages remediation for this cloud service. The affected version explicitly stated is 16.0.1.

Successful exploitation could allow an unauthorized attacker to execute code locally, potentially leading to full compromise of the affected system's confidentiality, integrity, and availability. No known exploits in the wild have been reported.

An official fix is available from Microsoft. Users and administrators should apply the provided update for Microsoft 365 Apps for Enterprise version 16.0.1 as detailed in the Microsoft advisory (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55036). Since this is a cloud-hosted service, Microsoft manages remediation server-side. Verify that the environment is updated accordingly.