Junos OS: MX Series: Services card might restart due to a race condition when DNS filtering is enabled.

When DNS filtering is enabled on Juniper Networks Junos MX Series with one of the following cards MS-PIC, MS-MIC or MS-MPC, an incoming stream of packets processed by the Multiservices PIC Management Daemon (mspmand) process might be bypassed due to a race condition. Due to this vulnerability, mspmand process, responsible for managing "URL Filtering service", can crash, causing the Services PIC to restart. While the Services PIC is restarting, all PIC services including DNS filtering service (DNS sink holing) will be bypassed until the Services PIC completes its boot process. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S8; 18.3 versions prior to 18.3R3-S1; 18.4 versions prior to 18.4R3; 19.1 versions prior to 19.1R3; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R3. This issue does not affect Juniper Networks Junos OS 17.4, 18.1, and 18.2.