CVE-2026-50447 is a Windows Message Queuing Service (MSMQ) remote code execution vulnerability caused by a heap-based buffer overflow. Microsoft rates it as Critical with a CVSS v3.1 base score of 9.8 and temporal score of 8.5. The vector is NETWORK, LOW attack complexity, NO privileges required, NO user interaction, and unchanged scope, with HIGH confidentiality, integrity, and availability impact. Microsoft reports no public disclosure and no known exploitation, and exploit code maturity is UNPROVEN. Because it is remotely reachable and requires no user interaction, it is a high-risk issue for enterprise systems that expose MSMQ to untrusted networks.

Highlights:
- CVSS scores: Base 9.8 - Temporal 8.5
- Exploit status & code maturity: Publicly Disclosed: No; Exploited: No; Exploit Code Maturity: UNPROVEN
- Impact: Remote Code Execution with HIGH confidentiality, integrity, and availability impacts
- Exploitation likelihood: Exploitation Less Likely; despite the network vector, Microsoft does not currently indicate active exploitation or mature exploit code
- Severity for enterprise: Critical severity; remotely exploitable with no privileges and no user interaction, so network-exposed MSMQ deployments are higher risk
- Patch status: available; customer action required

Affected systems:
- Windows 10 1607, 1809, 21H2, 22H2
- Windows 11 24H2, 25H2, 26H1, unspecified
- Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025