CVE-2018-19789: Malicious File Upload

An issue was discovered in Symfony 2.7.x before 2.7.50, 2.8.x before 2.8.49, 3.x before 3.4.20, 4.0.x before 4.0.15, 4.1.x before 4.1.9, and 4.2.x before 4.2.1. When using the scalar type hint string in a setter method (e.g. setName(string $name)) of a class that's the dataclass of a form, and when a file upload is submitted to the corresponding field instead of a normal text input, then UploadedFile::toString() is called which will then return and disclose the path of the uploaded file. If combined with a local file inclusion issue in certain circumstances this could escalate it to a Remote Code Execution.