Security Alert: [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