Microsoft Office Preview Pane Flaw Enables Zero-Click Remote Code Execution

Microsoft patched a critical Microsoft Office vulnerability, tracked as CVE-2025-30377, that can allow remote code execution when a specially crafted email attachment is processed in Outlook’s Preview Pane. The flaw was described as a use-after-free memory corruption issue tied to improper pointer management in Office, and exploitation reportedly requires little to no user interaction, making it effectively a zero-click threat during normal email handling.

Affected products reportedly included Microsoft 365 Apps, Office 2016 through Office 2024, and Office Online Server 2019 through 2025 before the May 2025 security updates. Security guidance urged organizations to deploy Microsoft’s patches quickly, consider temporarily disabling Outlook preview features, strengthen email filtering, and monitor for unusual Office process behavior, suspicious attachments, and anomalous email or authentication activity because successful exploitation could enable malware installation, credential theft, unauthorized access, and wider enterprise compromise.