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Microsoft Security Response CenterCVE-2026-55133

Microsoft OneNote Remote Code Execution Vulnerability

HighVendor CVSS 7.8 / 10 1 CVE Published Jul 14, 2026 at 7:00 AM UTC

Summary

Heap-based buffer overflow in Microsoft Office OneNote allows an unauthorized attacker to execute code locally.

Products covered

  • Microsoft 365 Apps for Enterprise for 32-bit Systems

  • Microsoft 365 Apps for Enterprise for 64-bit Systems

  • Microsoft Office 365 for Mac

  • Microsoft Office LTSC for Mac 2021

  • Microsoft Office LTSC for Mac 2024

Remediation

Click to Run Release Notes

Vendor-listed fixes

  • https://aka.ms/OfficeSecurityReleases

  • 16.111.26071215

CVEs in this advisory 1

Updates

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

  3. Confirmed at the source

    Our collector saw this advisory during a later source check.