CVE-2026-56164

Published Jul 14, 2026

Last updated a month ago

Exploit known CVSS medium 5.3

lms

Cloud

Network

Zero-day

Server

Overview

AI description

Automated description summarized from trusted sources.

CVE-2026-56164 is a missing authentication for critical function vulnerability found in Microsoft SharePoint Server. This flaw allows an unauthorized attacker to elevate privileges over a network. The vulnerability affects all supported on-premises SharePoint Server versions, including Subscription Edition, 2019, and 2016. It has been actively exploited in the wild as a zero-day, enabling cyber threat actors to gain unauthorized access to SharePoint Server instances and potentially engage in post-exploitation activities.

Description: Missing authentication for critical function in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.
Source: secure@microsoft.com
NVD status: Undergoing Analysis

Risk scores

CVSS 3.1

Type: Secondary
Base score: 5.3
Impact score: 1.4
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Severity: MEDIUM

Known exploits

Data from CISA

Vulnerability name: Microsoft SharePoint Server Missing Authentication for Critical Function Vulnerability
Exploit added on: Jul 14, 2026
Exploit action due: Jul 17, 2026
Required action: 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.

Weaknesses

secure@microsoft.com: CWE-306

Hype score: Not currently trending

References

Sources include official advisories and independent security research.