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.
The product constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component. Without sufficient removal or quoting of SQL syntax in user-controllable inputs, the generated SQL query can cause those inputs to be interpreted as SQL instead of ordinary user data.