CVE intelligenceCISA KEV

CVE-2026-56164

Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability

Published Jul 14, 2026Sources checked Sep 28, 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. Review the linked vendor advisory and apply the mitigation or fixed release for your affected product.

Microsoft Security Response Center: Exploitation reported by Microsoft Security Response Center (2026-07-14)

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.