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vmbus
About this tag
The vmbus tag on WindowsForum.com covers discussions about the VMBus, a synthetic communication channel used in Microsoft Hyper-V for high-performance data exchange between the host and virtual machines. Topics include troubleshooting unknown VMBus devices in Device Manager, particularly in the context of Automatic Virtual Machine Activation (AVMA), and security vulnerabilities affecting VMBus-related components. A notable thread addresses CVE-2025-49734, a local privilege elevation flaw in PowerShell Direct that exploits improper restriction of a communication channel in Windows PowerShell, impacting Hyper-V hosts. These discussions are relevant for IT professionals managing Hyper-V environments, focusing on device recognition issues and security updates.
Microsoft’s Security Update Guide entry for CVE-2025-49734 describes an improper restriction of a communication channel in Windows PowerShell—a flaw in the PowerShell Direct pathway that can let an authorized local attacker elevate privileges on an affected host if the required conditions are...