This security update resolves a publicly disclosed vulnerability in Microsoft Windows. The vulnerability could allow elevation of privilege if an attacker sends a specially crafted input/output control (IOCTL) request to the Message Queuing service. Successful exploitation of this vulnerability could lead to full access to the affected system. By default, the Message Queuing component is not installed on any affected operating system edition and can only be enabled by a user with administrative privileges. Only customers who manually enable the Message Queuing component are likely to be vulnerable to this issue.