Denial of service binding form from JSON in Play Framework

Summary

Play Framework is a web framework for Java and Scala. A denial of service vulnerability has been discovered in verions 2.8.3 through 2.8.15 of Play's forms library, in both the Scala and Java APIs. This can occur when using either the `Form#bindFromRequest` method on a JSON request body or the `Form#bind` method directly on a JSON value. If the JSON data being bound to the form contains a deeply-nested JSON object or array, the form binding implementation may consume all available heap space and cause an `OutOfMemoryError`. If executing on the default dispatcher and `akka.jvm-exit-on-fatal-error` is enabled—as it is by default—then this can crash the application process. `Form.bindFromRequest` is vulnerable when using any body parser that produces a type of `AnyContent` or `JsValue` in Scala, or one that can produce a `JsonNode` in Java. This includes Play's default body parser. This vulnerability been patched in version 2.8.16. There is now a global limit on the depth of a JSON object that can be parsed, which can be configured by the user if necessary. As a workaround, applications that do not need to parse a request body of type `application/json` can switch from the default body parser to another body parser that supports only the specific type of body they expect.