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Microsoft Security Response CenterCVE-2026-56156

Microsoft Excel Remote Code Execution Vulnerability

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

Read the vendor bulletin Get alerts for Microsoft 365 Apps for Enterprise for 32-bit Systems
7.8CVSS out of 10High severity
Scope

What the vendor says is affected

  • Microsoft 365 Apps for Enterprise for 32-bit Systems
  • Microsoft 365 Apps for Enterprise for 64-bit Systems
  • Microsoft Office LTSC for Mac 2021
  • Microsoft Office LTSC 2021 for 64-bit editions
  • Microsoft Office LTSC 2021 for 32-bit editions
  • Microsoft Office LTSC 2024 for 32-bit editions
  • Microsoft Office LTSC 2024 for 64-bit editions
  • Microsoft Office LTSC for Mac 2024
  • Microsoft Office 365 for Mac

Versions the vendor lists as fixed

  • https://aka.ms/OfficeSecurityReleases
  • 16.111.26071215
Next step

What the vendor recommends

Click to Run Release Notes

Review the complete instructions on the vendor's site
Timeline

When this advisory changed

  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.

Vulnerabilities

CVEs named in this advisory

CVE-2026-56156View CVSS, KEV, EPSS, and threat context
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