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CVE-2023-21554 / CVE-2023-21769 / CVE-2023-28302 are vulnerabilities in the Microsoft Message Queue (MSMQ) service. The most severe, CVE-2023-21554 is a low complexity unauthenticated remote code execution (RCE) vulnerability affecting all versions of Windows. It is CVSS-scored 9.8 out of 10 Critical and assessed by Microsoft as “Exploitation More Likely”. MSMQ is an optional service not installed by default, but it can be enabled by users or by installation of applications that depend on it.
The service status can also be retrieved in PowerShell: Get-WindowsOptionalFeature -Online -Featurename MSMQ*
Where Windows endpoints cannot be patched or patches are no longer supported, the MSMQ service should be disabled or removed.
Look up how to remove Windows features - this one is significant and is being exploited