CVE-2026-78510 – Microsoft Office Outlook Remote Code Execution Vulnerability

CVSS 9.8 CRITICAL Critical - Same Day Deployment

“A malicious RTF file can turn Outlook content into a path for remote code execution, with no privileges or user interaction required.”

CVE-2026-78510 is a critical heap-based buffer overflow vulnerability in Microsoft Office Outlook that can allow an unauthenticated attacker to execute arbitrary code over a network. An attacker can craft a malicious RTF file that triggers the vulnerability when opened or rendered in the Preview Pane. Successful exploitation can compromise confidentiality, integrity, and availability with code executing in the user’s context.

Key Details

Affected Product
Microsoft 365 Apps
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
CWE Classification
CWE-122
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