This vulnerability (CVE-2026-55134) is a stack-based buffer overflow in Microsoft Office Word, part of Microsoft 365 Apps for Enterprise. It allows an unauthorized attacker to execute arbitrary code locally, potentially leading to full compromise of the affected system. The CVSS 3.1 base score is 7.8 (high severity), with attack vector local, low attack complexity, no privileges required, and user interaction required. The vulnerability affects version 16.0.1. Microsoft has released an official fix and manages remediation for this cloud service. No known exploits are reported in the wild as of the publication date.

Successful exploitation can lead to local code execution with full confidentiality, integrity, and availability impact on the affected system. This means an attacker could run arbitrary code, potentially taking control of the affected device. However, exploitation requires local access and user interaction.

An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages the remediation process. Users and administrators should apply the official update as provided in the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55134 to mitigate this vulnerability.