Juniper Junos 12.1X44 before 12.1.X44-D20 and 12.1X45 before 12.1X45-D15, when the no-validate option is enabled, does not properly handle configuration validation errors during the config commit phase of the boot-up sequence, which allows remote attackers to bypass authentication via unspecified vectors.
https://kb.juniper.net/InfoCenter/index?page=content&id=JSA10593