This vulnerability (CVE-2026-55141) is a stack-based buffer overflow in Microsoft Office Excel, part of Microsoft 365 Apps for Enterprise. It permits local code execution by an unauthorized attacker. The CVSS 3.1 base score is 7.8, reflecting high impact on confidentiality, integrity, and availability. 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 at this time.

Successful exploitation allows an unauthorized attacker to execute arbitrary code locally, potentially leading to full compromise of the affected system's confidentiality, integrity, and availability. This could enable privilege escalation or further attacks on the host environment.

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 are updated to the fixed version as per the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55141. No additional mitigation steps are required beyond applying the official patch.