CVE-2026-88197: CWE-122: Heap-based Buffer Overflow in Microsoft Microsoft 365 Apps for Enterprise

This vulnerability (CVE-2026-88197) involves a heap-based buffer overflow in Microsoft 365 Apps for Enterprise, specifically Microsoft Office components. It enables an attacker without privileges to execute arbitrary code remotely by exploiting the overflow condition. The vulnerability affects multiple versions including 16.0.0, 16.0.1, and ranges from 16.0.0 up to but not including 16.0.17932.21056 and 16.0.1 up to but not including 16.0.14334.20974. Microsoft has published an official fix and manages patching for this cloud service. The CVSS 3.1 vector indicates network attack vector, low complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability.

Successful exploitation allows remote code execution by an unauthorized attacker, potentially leading to full compromise of the affected Microsoft 365 Apps for Enterprise environment. The impact includes complete loss of confidentiality, integrity, and availability of the affected system.

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 installations are updated to the fixed versions as per the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88197.