What are some potential security risks to consider when handling user input in PHP forms?

One potential security risk when handling user input in PHP forms is the possibility of SQL injection attacks. To prevent this, it is important to sanitize and validate user input before using it in database queries. This can be done using functions like mysqli_real_escape_string() or prepared statements. 

// Sanitize user input to prevent SQL injection
$user_input = mysqli_real_escape_string($connection, $_POST['user_input']);

// Validate user input to ensure it meets specific criteria
if (!preg_match("/^[a-zA-Z ]*$/", $user_input)) {
    echo "Invalid input. Please enter only letters and spaces.";
} else {
    // Proceed with using the sanitized user input in database queries
}

Keywords

SQL injection Cross-site scripting (XSS) Data validation Sanitization CSRF (Cross-Site Request Forgery)

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