CVE-2026-50387: CWE-121: Stack-based Buffer Overflow in Microsoft Microsoft Office 365 for Mac

This vulnerability (CVE-2026-50387) involves a stack-based buffer overflow in Windows GDI within Microsoft Office 365 for Mac. The flaw enables an authorized attacker with local access to escalate privileges on the affected system. The CVSS 3.1 score is 7.8, indicating high severity with high impact on confidentiality, integrity, and availability. Microsoft has published an official fix and manages remediation for this cloud-hosted service. There are no known exploits in the wild at this time.

Successful exploitation allows an authorized local attacker to elevate privileges, potentially gaining higher-level access to the system. The impact includes full compromise of confidentiality, integrity, and availability of affected components.

An official fix is available from Microsoft. Since Microsoft Office 365 for Mac is a cloud service, Microsoft manages the remediation server-side. Users and administrators should ensure that their environments are updated according to Microsoft's guidance at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50387.