Microsoft Issues Urgent Friday WSUS Security Update

October 24, 2025

Microsoft published an unscheduled security patch on Friday addressing a severe vulnerability in Windows Server Update Services (WSUS), creating weekend work for system administrators.

CVE-2025-59287 Explained

The patch fixes a remote code execution weakness spanning Windows Server 2012 to 2025. The flaw involves unsafe handling of serialized untrusted data, enabling attackers without credentials to run malicious code. Working proof-of-concept code exists online.

Microsoft rated this vulnerability at their top severity level. Systems running the WSUS role face exposure.


Temporary Protection Measures

For those unable to apply the patch immediately, Microsoft suggests two options: turn off the WSUS role entirely (though this halts client update distribution), or configure firewalls to reject traffic on ports 8530 and 8531.

The patch combines October's security fixes for systems missing them. Systems require restart after installation.


Legacy Technology Concerns

Microsoft identified the weakness as involving an outdated serialization approach. Older code within Windows Server continues creating security challenges demanding rapid fixes.


WSUS Future Uncertain

Microsoft no longer actively develops WSUS, though support continues. Following customer feedback, the company recently walked back plans to discontinue driver synchronization capabilities in April 2025.

Microsoft encourages administrators to migrate toward cloud alternatives like Intune rather than maintain on-premises update infrastructure.


Why This Matters

Unscheduled security releases indicate serious threats, especially for components no longer under active development. Though Microsoft hasn't set a retirement date, this severe vulnerability highlights concerns about WSUS's ongoing sustainability.


Professional Security Update Management

At Altiatech, our managed IT services offer continuous monitoring and expert handling of critical security patches, ensuring proper testing and deployment without operational interruption.


Get in touch:

📧 Email: innovate@altiatech.com
📞 Phone (UK): +44 (0)330 332 5482


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