CVE intelligenceCISA KEV

CVE-2026-56164

Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability

Published Jul 14, 2026Sources checked Nov 12, 2026

9.8CRITICALCVSS out of 10

What this means

Actively exploited

CISA lists CVE-2026-56164 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Microsoft SharePoint Server.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Public exploit: Not collected.

Microsoft Security Response Center: Exploitation reported by Microsoft Security Response Center (2026-07-14)
Microsoft exploitation status: Exploited:Yes

What to do next

Remediation and response

Review the linked vendor advisory and apply the mitigation or fixed release for your affected product.

Microsoft Security Response Center guidance

Vendor revision: Jul 14, 2026

Vendor remediation details

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.

Vendor-listed releases

16.0.5561.1001
16.0.10417.20175
16.0.19725.20434

CISA KEVListedObserved exploitation

EPSS1.0%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors1Source-linked actor relationships

Overview

What is CVE-2026-56164?

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

Source: NVD

Reported activity: Microsoft exploitation status: Exploited:Yes
Microsoft Security Response Center · Published Jul 14, 2026

CISA says:Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.CISA catalog due date Jul 17, 2026