This vulnerability (CVE-2026-55041) involves a heap-based buffer overflow in Microsoft Office Excel, part of Microsoft 365 Apps for Enterprise. The flaw enables an unauthorized attacker to execute arbitrary code locally. The CVSS 3.1 score is 7.8, reflecting high impact on confidentiality, integrity, and availability. The vulnerability requires local attack vector with low attack complexity and no privileges required but user interaction is needed. Microsoft has published an official fix and manages remediation for this cloud service. No active exploitation has been reported.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code on the affected system, potentially leading to full compromise of confidentiality, integrity, and availability of the application and possibly the host. However, exploitation requires local access and user interaction. No known exploits are currently active in the wild.

An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages remediation server-side. Users and administrators should ensure that their Microsoft 365 Apps for Enterprise installations are updated according to the vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55041 to mitigate this vulnerability.