SQL injection in index_chart_data action

InstantCMS is a free and open source content management system. A SQL injection vulnerability affects instantcms v2.16.2 in which an attacker with administrative privileges can cause the application to execute unauthorized SQL code. The vulnerability exists in index_chart_data action, which receives an input from user and passes it unsanitized to the core model `filterFunc` function that further embeds this data in an SQL statement. This allows attackers to inject unwanted SQL code into the statement. The `period` should be escaped before inserting it in the query. As of time of publication, a patched version is not available.