What are some potential security risks associated with email functionality in PHP scripts?

One potential security risk associated with email functionality in PHP scripts is the possibility of email injection attacks. This occurs when malicious users inject additional headers into the email message, potentially leading to spamming or phishing activities. To mitigate this risk, it is important to sanitize and validate user input before using it in email headers.

// Sanitize and validate email input
$email = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);

// Set additional headers to prevent email injection
$additional_headers = "From: myemail@example.com\r\n";
$additional_headers .= "Reply-To: myemail@example.com\r\n";

// Send email using safe email input and additional headers
mail($email, "Subject", "Message", $additional_headers);