Stock-Inventory-Management-System: Unauthenticated SQL Injection and Hardcoded Credentials in login.php Enable Full Authentication Bypass

The Stock-Inventory-Management-System application's login.php assigns raw $_POST username/password values to $_SESSION and builds its authentication query by directly concatenating those session values into a SQL statement with no parameterization or escaping. An unauthenticated remote attacker can submit a payload such as ' OR '1'='1 in the login form to bypass authentication entirely. The same script additionally contains hardcoded administrative credentials (admin/neola) in a post-login conditional check, providing a second, independent full-authentication-bypass path.