The LogIn-SignUp project by VishnuSivadasVS is vulnerable to SQL Injection due to unsafe construction of SQL queries in DataBase.php. The functions logIn() and signUp() build queries by directly concatenating user input and unvalidated table names without using prepared statements. While a prepareData() function exists, it is insufficient to prevent SQL injection and does not sanitize the table name.
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.