This vulnerability (CVE-2026-55029) involves a heap-based buffer overflow in Microsoft Office Excel, part of Microsoft 365 Apps for Enterprise. It enables unauthorized local code execution. The CVSS 3.1 vector indicates low attack complexity, no privileges required, and user interaction is needed. Confidentiality, integrity, and availability impacts are all high. Microsoft has published an official fix and manages remediation for this cloud-hosted service. No known exploits are reported in the wild as of the publication date.

Successful exploitation could allow an attacker to execute arbitrary code locally, potentially leading to full compromise of the affected Microsoft 365 Apps for Enterprise environment. The vulnerability affects confidentiality, integrity, and availability with high impact. However, exploitation requires user interaction and local 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 ensure their Microsoft 365 Apps for Enterprise are updated according to Microsoft's guidance at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55029. No additional mitigation actions are required beyond applying the official fix.