The Translate Multilingual sites WordPress plugin before 2.3.3 is vulnerable to an authenticated SQL injection. By adding a new language (via the settings page) containing specific special characters, the backticks in the SQL query can be surpassed and a time-based blind payload can be injected.
https://wpscan.com/vulnerability/1fa355d1-cca8-4b27-9d21-0b420a2e1bf3
http://packetstormsecurity.com/files/171479/WordPress-Translatepress-Multilingual-SQL-Injection.html