Whoogle Search Cross-site Scripting vulnerability

Whoogle Search is a self-hosted metasearch engine. In versions 0.8.3 and prior, the `element` method in `app/routes.py` does not validate the user-controlled `src_type` and `element_url` variables and passes them to the `send` method which sends a `GET` request on lines 339-343 in `requests.py`. The returned contents of the URL are then passed to and reflected back to the user in the `send_file` function on line 484, together with the user-controlled `src_type`, which allows the attacker to control the HTTP response content type leading to a cross-site scripting vulnerability. An attacker could craft a special URL to point to a malicious website and send the link to a victim. The fact that the link would contain a trusted domain (e.g. from one of public Whoogle instances) could be used to trick the user into clicking the link. The malicious website could, for example, be a copy of a real website, meant to steal a person’s credentials to the website, or trick that person in another way. Version 0.8.4 contains a patch for this issue.