CVE-2026-56164: Microsoft SharePoint Server Elevation of Privilege Vulnerability

Overview

Severity
Medium (CVSS 5.3)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:F/RL:O/RC:C
Category
Elevation of Privilege
Exploit Status
Actively Exploited
Exploitation Likelihood
Detected
Patch Tuesday
2026-Jul
Released
2026-07-14

Description

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

FAQ

According to the CVSS metric, the attack vector is network (AV:N) and the attack complexity is low (AC:L). What does that mean for this vulnerability? The attack vector is Network (AV:N) because this vulnerability is remotely exploitable and can be exploited from the internet. The attack complexity is Low (AC:L) because an attacker does not require significant prior knowledge of the system and can achieve repeatable success with the payload against the vulnerable component. I am running SharePoint Server 2016. Do the updates for SharePoint Enterprise Server 2016 also apply to the version I am running? Yes. The same KB number applies to both SharePoint Server 2016 and SharePoint Enterprise Server 2016. Customers running either version should install the security update to be protected from this vulnerability.

Affected Products (3)

Microsoft Office

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

Security Updates (3)

Acknowledgments

Anonymous, Genwei Jiang with <a href="https://cloud.google.com/security/mandiant">Google Cloud, FLARE OTF</a>, Jayson Frost with <a href="https://cloud.google.com/security/consulting/mandiant-incident-response-services">Mandiant Incident Response</a>

Revision History

  • 2026-07-14: Information published.