Overview
Recently, NSFOCUS CERT detected that Microsoft released a security update that fixed the Windows Server Update Service (WSUS) remote code execution vulnerability (CVE-2025-59287); Because WSUS’s GetCookie does not perform type verification when processing objects, an unauthenticated attacker can achieve remote code execution by deserializing malicious data to control the target server. The CVSS score is 9.8. At present, the vulnerability PoC has been made public. Relevant users are requested to take measures to protect it as soon as possible.
Windows Server Update Services (WSUS) is a server role provided by Microsoft to centrally manage and distribute updates for Microsoft products, supporting security patches for products including Windows operating systems, Office, Exchange Server and SQL Server, Key updates, drivers and service packs.
Reference link: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59287
Scope of Impact
Affected versions
- Windows Server 2012
- Windows Server 2012 (Server Core installation)
- Windows Server 2012 R2
- Windows Server 2012 R2 (Server Core installation)
- Windows Server 2016
- Windows Server 2016 (Server Core installation)
- Windows Server 2019
- Windows Server 2019 (Server Core installation)
- Windows Server 2022
- Windows Server 2022 (Server Core installation)
- Windows Server 2022, 23H2 Edition (Server Core installation)
- Windows Server 2025
- Windows Server 2025 (Server Core installation)
Mitigation
At present, Microsoft has officially released a security patch to fix the vulnerability for supported product versions. It is recommended that affected users install the patch as soon as possible for protection. Download link: https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-59287
Note: Patch updates for Windows Update may fail due to network problems, computer environment problems, etc. After installing the patch, users should check whether the patch has been successfully updated in time.
Right-click the Windows icon, select “Settings (N)”, select “Update and Security”-“Windows Update”, view the prompt information on this page, or click “View Update History” to view the historical update status.
For updates that have not been successfully installed, you can click the update name to jump to the Microsoft official download page. It is recommended that users click the link on this page and go to the “Microsoft Update Catalog” website to download the independent program package and install it.
Statement
This advisory is only used to describe a potential risk. NSFOCUS does not provide any commitment or promise on this advisory. NSFOCUS and the author will not bear any liability for any direct and/or indirect consequences and losses caused by transmitting and/or using this advisory. NSFOCUS reserves all the rights to modify and interpret this advisory. Please include this statement paragraph when reproducing or transferring this advisory. Do not modify this advisory, add/delete any information to/from it, or use this advisory for commercial purposes without permission from NSFOCUS.
About NSFOCUS
NSFOCUS, a pioneering leader in cybersecurity, is dedicated to safeguarding telecommunications, Internet service providers, hosting providers, and enterprises from sophisticated cyberattacks.
Founded in 2000, NSFOCUS operates globally with over 4000 employees at two headquarters in Beijing, China, and Santa Clara, CA, USA, and over 50 offices worldwide. It has a proven track record of protecting over 25% of the Fortune Global 500 companies, including four of the five largest banks and six of the world’s top ten telecommunications companies.
Leveraging technical prowess and innovation, NSFOCUS delivers a comprehensive suite of security solutions, including the Intelligent Security Operations Platform (ISOP) for modern SOC, DDoS Protection, Continuous Threat Exposure Management (CTEM) Service and Web Application and API Protection (WAAP). All the solutions and services are augmented by the Security Large Language Model (SecLLM), ML, patented algorithms and other cutting-edge research achievements developed by NSFOCUS.
