Inventory-Management-System-PHP - Unauthenticated SQL Injection in Login and Product Deletion

Inventory-Management-System-PHP's login.php constructs its authentication query via direct string concatenation of raw POST parameters: = "select * from user where email = '' and password = ''", with no escaping or parameterization, allowing authentication bypass via a payload such as email=' OR 1=1 LIMIT 1-- -.