In recent years, vehicles became able to establish connections with other vehicles and infrastructure units that are located in the roadside. In the near future, the vehicular network will be expanded to include the communication between vehicles and any smart devices in the roadside which is called Vehicle-to-Everything (V2X) communication. The vehicular network causes many challenges due to heterogeneous nodes, various speeds and intermittent connection, where traditional security methods are not always efficacious. As a result, an extensive variety of research works has been done on optimizing security solutions whilst considering network requirements. In this paper, we present a comprehensive survey and taxonomy of the existing security solutions for V2X communication technology. Then, we provide discussions and comparisons with regard to some pertinent criteria. Also, we present a threat analysis for V2X enabling technologies. Finally, we point out the research challenges and some future directions.

48 pages, 5 figures, 3 tables, it has been accepted by Computer Networks on 29th December 2018