The factory configuration for vMX installations, as shipped, includes default credentials for the root account. Without proper modification of these default credentials by the administrator, an attacker could exploit these credentials and access the vMX instance without authorization. This issue affects Juniper Networks Junos OS: 17.1 versions prior to 17.1R2-S11, 17.1R3-S2 on vMX; 17.2 versions prior to 17.2R3-S3 on vMX; 17.3 versions prior to 17.3R2-S5, 17.3R3-S7 on vMX; 17.4 versions prior to 17.4R2-S9, 17.4R3 on vMX; 18.1 versions prior to 18.1R3-S9 on vMX; 18.2 versions prior to 18.2R2-S7, 18.2R3-S3 on vMX; 18.2X75 versions prior to 18.2X75-D420, 18.2X75-D60 on vMX; 18.3 versions prior to 18.3R1-S7, 18.3R2-S3, 18.3R3-S1 on vMX; 18.4 versions prior to 18.4R1-S5, 18.4R2-S3, 18.4R3 on vMX; 19.1 versions prior to 19.1R1-S4, 19.1R2, 19.1R3 on vMX; 19.2 versions prior to 19.2R1-S3, 19.2R2 on vMX; 19.3 versions prior to 19.3R1-S1, 19.3R2 on vMX.