| This Multi-State Information Sharing and Analysis Center (MS-ISAC) Advisory is being provided to assist agencies and organizations in guarding against the persistent malicious actions of cybercriminals. |
| A vulnerability has been discovered in Microsoft Windows Server Update Services (WSUS) which could allow for remote code execution. WSUS is a tool that helps organizations manage and distribute Microsoft updates across multiple computers. Instead of every PC downloading updates from Microsoft’s servers, WSUS downloads the updates and stores them, then distributes them to all computers on the network that connect to it. Successful exploitation of the vulnerability could allow a threat actor to gain full control of the WSUS server and distribute malicious updates to client devices. |
| Threat Intelligence |
| Proof-of-concept exploit code was released according to open source reporting. Additionally, CISA added CVE-2025-59287 to the Known Exploited Vulnerabilities (KEV) catalog. |
| Systems Affected |
| Windows Server 2012 R2 versions prior to build 6.3.9600.22826 Windows Server 2012 versions prior to build 6.2.9200.25728 Windows Server 2016 versions prior to build 10.0.14393.8524 Windows Server 2025 versions prior to build 10.0.26100.6905 Windows Server 2022, 23H2 Edition (Server Core installation) versions prior to build 10.0.25398.1916 Windows Server 2022 versions prior to build 10.0.20348.4297 Windows Server 2019 versions prior to build 10.0.17763.7922 |
| Risk |
| Government: – Large and medium government entities: High – Small government entities: Medium |
| Businesses: – Large and medium business entities: High – Small business entities: Medium |
| Home Users: Low |
| Recommendations |
| Apply appropriate updates provided by Microsoft or other vendors which use this software to vulnerable systems immediately after appropriate testing. Apply the Principle of Least Privilege to all systems and services. Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack. Use vulnerability scanning to find potentially exploitable software vulnerabilities to remediate them. Architect sections of the network to isolate critical systems, functions, or resources. Use physical and logical segmentation to prevent access to potentially sensitive systems and information. Use a DMZ to contain any internet-facing services that should not be exposed from the internal network. Configure separate virtual private cloud (VPC) instances to isolate critical cloud systems. Use capabilities to detect and block conditions that may lead to or be indicative of a software exploit occurring. |
| References |