This vulnerability (CVE-2026-55123) is a heap-based buffer overflow in Microsoft Office PowerPoint, part of Microsoft 365 Apps for Enterprise. It enables an unauthorized attacker to execute code locally, potentially leading to full compromise of the affected system. The CVSS 3.1 score is 7.8 (high severity) with attack vector local, low attack complexity, no privileges required, user interaction required, and impacts to confidentiality, integrity, and availability rated high. The vulnerability affects version 16.0.1. Microsoft has issued an official fix and manages remediation for this cloud service. The vendor advisory is available at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55123.

Successful exploitation allows local code execution by an unauthorized attacker, resulting in high impact on confidentiality, integrity, and availability of the affected system. This could lead to full system compromise if exploited.

An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages remediation server-side. Users and administrators should apply the official update as directed in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55123 to mitigate this vulnerability.