[Updated] Microsoft Releases July 2026 Security Updates

JPCERT-AT-2026-0020
JPCERT/CC
2026-07-15(Initial)
2026-07-31(Update)

I. Overview

Microsoft has released July 2026 Security Updates to address the vulnerabilities in their products. Attackers leveraging these vulnerabilities may be able to execute arbitrary code remotely without authentication, etc.

Microsoft Corporation
July 2026 Security Updates
https://msrc.microsoft.com/update-guide/en-US/releaseNote/2026-Jul

According to Microsoft, among the vulnerabilities, the following vulnerabilities have been confirmed to be exploited in the wild. Please refer to the latest information provided by Microsoft and implement the measures described in "II. Solution."

CVE-2026-56164
Microsoft SharePoint Server Elevation of Privilege Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-56164

CVE-2026-56155
Active Directory Federation Services Elevation of Privilege Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-56155

Update: July 31, 2026 Update

Microsoft has updated its advisory and stated that the remote code execution vulnerability in SharePoint (CVE-2026-58644), which was addressed in this month's security updates, has been exploited in the wild.

CVE-2026-58644
Microsoft SharePoint Remote Code Execution Vulnerability
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58644

In addition, another remote code execution vulnerability (CVE-2026-50522)has been added to CISA's Known Exploited Vulnerabilities (KEV) Catalog.Information believed to include a proof-of-concept (PoC) exploit for this vulnerability has been published by a security researcher. Furthermore,watchTowr has reported observing attacks using the PoC exploit against its honeypots and published information indicating that machine keys were stolen from vulnerable SharePoint Server.

CVE-2026-50522
Microsoft SharePoint Remote Code Execution Vulnerability
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50522

watchTowr
CVE-2026-50522 Exploitation Alert: SharePoint On-Premise Vulnerability
https://www.linkedin.com/posts/watchtowr_exploitation-alert-watchtowr-is-observing-activity-7485278595850940416-LSP8/

CISA
Known Exploited Vulnerabilities Catalog CVE-2026-50522
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-50522

As information regarding the exploitation of these vulnerabilities has been made publicly available, organizations using SharePoint Server are strongly advised to promptly apply the necessary mitigations and investigate their systems.

II. Solution

Please apply the security update programs through Microsoft Update, Windows Update, etc.

Microsoft Update Catalog
https://www.catalog.update.microsoft.com/

Windows Update: FAQ
https://support.microsoft.com/en-us/help/12373/windows-update-faq

III. References

Microsoft Corporation
Release Notes
https://msrc.microsoft.com/update-guide/

Update: July 31, 2026 Update

Support for SharePoint Server 2019 and SharePoint Server 2016 ended on July 14, 2026. Users are encouraged to migrate to supported versions of the product.

SharePoint Server 2019
https://learn.microsoft.com/lifecycle/products/sharepoint-server-2019

SharePoint Server 2016
https://learn.microsoft.com/lifecycle/products/sharepoint-server-2016

If you have any information regarding this alert, please contact JPCERT/CC.

Revision History

2026-07-15 First edition
2026-07-31 Updated "I. Overview" and "III. References"
2026-07-31 Updated information about exploit status of CVE-2026-50522

JPCERT Coordination Center (Cyber Security Coordination Group)
MAIL: ew-info@jpcert.or.jp
https://www.jpcert.or.jp/english/

Top