This vulnerability (CVE-2026-55948) is a use-after-free issue (CWE-416) in Microsoft Office Excel, part of Microsoft 365 Apps for Enterprise. It enables an unauthorized attacker to execute code locally on the affected system. The CVSS v3.1 score is 7.8, indicating high severity, with 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 could allow an unauthorized attacker to execute arbitrary code locally, potentially leading to full compromise of the affected system's confidentiality, integrity, and availability. The vulnerability is rated high severity with CVSS 7.8. No active exploitation is currently known.

An official fix is available from Microsoft. Users should apply the update for Microsoft 365 Apps for Enterprise version 16.0.1 as provided in the Microsoft security advisory. Since this is a cloud-hosted service, Microsoft manages remediation server-side. Refer to the Microsoft update guide for detailed patching instructions.