CVE-2026-97772: CWE-415: Double Free in Microsoft Microsoft 365 Apps for Enterprise

CVE-2026-97772 is a double free vulnerability (CWE-415) in Microsoft Office Excel within Microsoft 365 Apps for Enterprise. This flaw enables remote code execution by an unauthorized attacker over a network. The vulnerability affects several specific versions of the product, including versions 16.0.0, 16.0.1, and ranges from 16.0.0 up to but not including 16.0.14334.20974, 16.0.17932.21056, and 16.0.10417.20228. Microsoft has published an official fix for this vulnerability, and it is tracked with a CVSS 3.1 score of 8.8, indicating high severity. The vendor advisory is available at the Microsoft Security Response Center.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code remotely without requiring privileges, potentially leading to full compromise of the affected system. The impact includes complete confidentiality, integrity, and availability loss as indicated by the CVSS vector.

An official fix is available from Microsoft. Users and administrators should apply the security updates provided by Microsoft for Microsoft 365 Apps for Enterprise as detailed in the vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-97772. Since this is a cloud service, Microsoft manages remediation for the cloud-hosted components. Ensure that all affected versions are updated to the fixed versions as per the advisory.