What are the potential consequences of not properly validating and sanitizing user input in PHP code?

Not properly validating and sanitizing user input in PHP code can lead to security vulnerabilities such as SQL injection, cross-site scripting (XSS), and other forms of attacks. To mitigate these risks, it is important to validate and sanitize all user input before using it in your application. 

// Example of properly validating and sanitizing user input
$user_input = $_POST['user_input'];

// Validate user input
if (!filter_var($user_input, FILTER_VALIDATE_EMAIL)) {
    // Invalid input, handle error
    die("Invalid email address");
}

// Sanitize user input
$clean_input = htmlspecialchars($user_input);

// Now $clean_input can be safely used in your application

Keywords

SQL injection cross-site scripting (XSS) security vulnerabilities htmlspecialchars filter_var

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