An issue was discovered in Symfony before 2.7.38, 2.8.31, 3.2.14, 3.3.13, 3.4-BETA5, and 4.0-BETA5. The Intl component includes various bundle readers that are used to read resource bundles from the local filesystem. The read() methods of these classes use a path and a locale to determine the language bundle to retrieve. The locale argument value is commonly retrieved from untrusted user input (like a URL parameter). An attacker can use this argument to navigate to arbitrary directories via the dot-dot-slash attack, aka Directory Traversal.
An issue was discovered in Symfony before 2.7.38, 2.8.31, 3.2.14, 3.3.13, 3.4-BETA5, and 4.0-BETA5. When a form is submitted by the user, the request handler classes of the Form component merge POST data and uploaded files data into one array. This big array forms the data that are then bound to the form. At this stage there is no difference anymore between submitted POST data and uploaded files. A user can send a crafted HTTP request where the value of a "FileType" is sent as normal POST data that could be interpreted as a local file path on the server-side (for example, "file:///etc/passwd"). If the application did not perform any additional checks about the value submitted to the "FileType", the contents of the given file on the server could have been exposed to the attacker.
The debug handler in Symfony before v2.7.33, 2.8.x before v2.8.26, 3.x before v3.2.13, and 3.3.x before v3.3.6 has XSS via an array key during exception pretty printing in ExceptionHandler.php, as demonstrated by a /_debugbar/open?op=get URI. NOTE: the vendor's position is that this is not a vulnerability because the debug tools are not intended for production use. NOTE: the Symfony Debug component is used by Laravel Debugbar
An issue was discovered in Symfony 2.7.x before 2.7.38, 2.8.x before 2.8.31, 3.2.x before 3.2.14, and 3.3.x before 3.3.13. DefaultAuthenticationSuccessHandler or DefaultAuthenticationFailureHandler takes the content of the _target_path parameter and generates a redirect response, but no check is performed on the path, which could be an absolute URL to an external domain. This Open redirect vulnerability can be exploited for example to mount effective phishing attacks.