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Microsoft Security Response CenterCVE-2026-56164

Microsoft SharePoint Server Elevation of Privilege Vulnerability

Missing authentication for critical function in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.

Read the vendor bulletin Get alerts for Microsoft SharePoint Enterprise Server
5.3CVSS out of 10Medium severity
Scope

What the vendor says is affected

  • Microsoft SharePoint Enterprise Server 2016
  • Microsoft SharePoint Server 2019
  • Microsoft SharePoint Server Subscription Edition

Versions the vendor lists as fixed

  • 16.0.5561.1001
  • 16.0.10417.20175
  • 16.0.19725.20434
Next step

What the vendor recommends

The following mitigating factors might be helpful in your situation: Enable AMSI: Ensure the Antimalware Scan Interface (AMSI) is actively integrated and scanning SharePoint and IIS worker process memory. Enable AMSI scan feature and set the Request Body Scan mode to Full in order for POST body payloads to be detected. Configure AMSI integration with SharePoint Server - https://learn.microsoft.com Install KB5002891. Install KB5002883. Install KB5002882.

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-2026-56164View CVSS, KEV, EPSS, and threat context
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