Microsoft Office for Mac Remote Code Execution Vulnerability CVE-2026-78511

A remote code execution vulnerability (CVE‑2026‑78511) was identified in Microsoft Office Word for macOS. The flaw allows an attacker to execute arbitrary code when a specially crafted document is opened.

What’s affected

• Microsoft Office for Mac (Word) – all versions prior to the latest security update
• Other Microsoft Office products and platforms are not impacted

Impact

Successful exploitation could give an attacker full control over the victim’s machine, enabling data exfiltration, persistence, or lateral movement.

Mitigation

Download and install the Office for Mac security update from Microsoft’s Release Notes (link: https://go.microsoft.com/fwlink/p/?linkid=831049). No action is required for Windows or other Office editions.

Microsoft recommends applying the update as soon as possible to prevent exploitation.