CVE-2026-65657

This vulnerability is like a “memory bookkeeping” mistake inside Microsoft Office. Under certain document conditions, Office can end up using freed memory in a way that lets an attacker run their own code on your device when you open the document. In a business setting, that can turn a malicious email attachment into a serious malware infection.

This matters if your business uses Microsoft Office (including Microsoft 365 Apps and the listed Office/macOS editions). Because the issue can be triggered by opening a crafted document, it creates risk around phishing and “unexpected attachment” scenarios. Act urgently if your Office is not yet updated to the fixed versions, especially when documents are frequently opened from email or the web.

This is RED because it is a high-impact remote code execution class bug in Microsoft Office and Microsoft has provided fixes across multiple Office editions. Even though there’s no public exploit code listed in the findings, press attention tied to the patch indicates active, real-world attacker focus (including Lazarus-group mentions). Update now rather than waiting for “later this week.”