What are some common security vulnerabilities that can arise in PHP scripts when processing form data?

One common security vulnerability when processing form data in PHP scripts is Cross-Site Scripting (XSS), where attackers inject malicious scripts into the form fields that are then displayed to other users. To prevent XSS attacks, always sanitize and validate user input before displaying it on the webpage. 

// Sanitize and validate user input before displaying it
$user_input = $_POST['user_input'];
$sanitized_input = htmlspecialchars($user_input, ENT_QUOTES, 'UTF-8');

echo "User input: " . $sanitized_input;

Keywords

SQL injection Cross-site scripting (XSS) Cross-site request forgery (CSRF) File upload vulnerabilities Input validation

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