WPSchoolPress < 2.1.10 – Multiple Authenticated SQL Injections | CVE 2021-24575

Description

The plugin does not properly sanitize or use prepared statements before using POST variable in SQL queries, leading to SQL injection in multiple actions available to various authenticated users, from simple subscribers/students to teachers and above.

Proof of Concept

In action "sendSubMessage", The plugin did not properly sanitize and escape the $main_m_id variable which is retrieved from $_POST['main_m_id'] this action can be targeted by any authenticated user.
In action "UpdateStudent", The plugin did not properly sanitize and escape the $id variable which is retrieved from $_POST['Class'] this action can be targeted by any authenticated  user.
In action "getstudentdate", The plugin did not properly sanitize and escape the $catid variable which is retrieved from $_POST['data'] this action can be targeted by any authenticated  user.
In action "AddStudent", The plugin did not properly sanitize and escape the $id variable  which is retrieved from $_POST['Class'] this action can be targeted by teacher+ user.
In action "addMark", The plugin did not properly sanitize and escape the $flid variable which is retrieved from $_POST['exmarks'] this action can be targeted by teacher+ user.
In action "savetimetable", The plugin did not properly sanitize and escape the $day variable which is retrieved from $_POST['day'] this action can be targeted by teacher+ user.
In action "AttendanceEntry", The plugin did not properly sanitize and escape the $stid or $class variable which is retrieved from $_POST['absent'] or $_POST['AttendanceClass']  this action can be targeted by teacher+ user.