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CVE-2026-78509CriticalMonitor

Microsoft Office Outlook Remote Code Execution Vulnerability

Severity Critical  ·  Urgency Monitor

Why it matters: Critical severity (CVSS 9.8)

Remote Code Execution · Critical · CVSS 9.8. Affects: Microsoft Office 365 for Mac, Microsoft Office, Microsoft 365 Apps, Microsoft Office LTSC for Mac, Microsoft Office LTSC, Microsoft Word.

CVSS 9.8Security update published 2026-09-08Applies to Cloud + on-premisesKB5002923NVD

Affected: Microsoft Office 365 for Mac, Microsoft Office, Microsoft 365 Apps, Microsoft Office LTSC for Mac, Microsoft Office LTSC, Microsoft Word

Related changes

Change history

2026-09-08 · First captured by tracker

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