Multiple Microsoft MSMQ Denial-of-Service Flaws Patched

Microsoft disclosed and patched a cluster of Microsoft Message Queuing (MSMQ) denial-of-service vulnerabilities affecting Windows systems, including CVE-2025-21230, CVE-2025-21290, CVE-2025-21270, CVE-2025-21289, and CVE-2025-21251. The issues were published through the Microsoft Security Response Center update guide and all identify MSMQ as the affected component, indicating that specially crafted traffic or message handling conditions could disrupt the service and impact application availability on systems where MSMQ is enabled.

The January disclosures followed an earlier MSMQ denial-of-service issue, CVE-2024-49096, showing continued security attention on the legacy messaging component across consecutive update cycles. Organizations using MSMQ should prioritize applying Microsoft security updates, verify whether the service is enabled on exposed or business-critical hosts, and assess operational dependencies because repeated flaws in the component raise the risk of service interruption if unpatched systems remain reachable.