Microsoft launched this urgent update on December 18, 2025, to address a functional breakdown in Message Queuing that appeared after the month's initial security releases. The problem primarily impacts Windows 10 versions 22H2 and 21H2, manifesting as inactive message queues that block applications from processing data. Users affected by the bug often encountered misleading error messages suggesting their systems were out of memory or disk space when the actual cause was the faulty software update.
The disruption is most severe for organizations utilizing Internet Information Services sites that depend on MSMQ for asynchronous processing. In large-scale enterprise environments or clustered systems operating under heavy loads, these queue failures can trigger a cascade of issues across distributed networks. While enterprise and managed infrastructures are at high risk, personal versions of Windows such as Home and Pro editions have generally remained unaffected by this specific technical regression.
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This new release is cumulative, meaning it includes all previous fixes from the December 9 patch cycle along with the emergency repair. Microsoft has bundled a servicing stack update within the package to improve the verification logic for devices hosted on Azure. This ensures that cloud-based infrastructure can continue to receive and install future updates without deployment complications or certificate verification failures.
IT administrators are advised to prioritize the deployment of this update across their networks immediately, especially where MSMQ is integrated with web services. Microsoft recommends that organizations verify their Azure-hosted devices have access to the necessary certificate update domains to ensure the installation succeeds. It is also standard practice for administrators to test the patch in a staging environment before pushing it to production systems to confirm compatibility.
While addressing this immediate crisis, Microsoft also issued a long-term warning regarding Secure Boot certificates which are set to expire in mid-2026. This future event could potentially interfere with the ability of devices to boot properly if not addressed in advance. Organizations are encouraged to review current certificate guidance now to create a proactive schedule for updates, thereby avoiding similar emergency scenarios in the coming year.
Source: Microsoft Releases Out Of Band Update To Patch MSMQ Bug Affecting IIS Websites
Solid breakdown of the MSMQ issue. The cascading failures in large enterprise environments are exactly what makes these queue breakdowns so dangerous, especially when dependecies span multiple services. I've dealt with similar issues where misleading error messages (memory/disk space) sent teams down the wrong troubleshooting path for hours. The Azure certificate verification bundling is smart, prevents another layer of potential failure during rollout.