This vulnerability (CVE-2026-55141) is a stack-based buffer overflow in Microsoft Office Excel, part of Microsoft 365 Apps for Enterprise. It enables an unauthorized attacker to execute arbitrary code locally, potentially leading to full compromise of confidentiality, integrity, and availability. The CVSS v3.1 score is 7.8, indicating high severity, with attack vector local, low attack complexity, no privileges required, and user interaction needed. Microsoft has published an official fix and manages remediation for this cloud service. No known exploits are reported in the wild at this time.

Successful exploitation allows local code execution with 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. Microsoft manages remediation for this cloud-hosted service. 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-2026-55141 to mitigate this vulnerability.