joi is a data validation library for JavaScript. In versions prior to 17.13.4 and 18.0.0 through 18.2.0, deeply nested input validated against recursive link() schemas triggers an uncaught RangeError. When validate() is called without try/catch in a request handler, this causes an unhandled exception that can crash the process, leading to denial of service. With validateAsync() or validate() inside try/catch, the validation fails but returns a RangeError instead of a structured ValidationError. Fixed in joi 17.13.4 and 18.2.1.