What are the common pitfalls to avoid when sending emails using PHP's mail function?

One common pitfall to avoid when sending emails using PHP's mail function is not properly sanitizing user input, which can lead to security vulnerabilities such as injection attacks. To solve this issue, always validate and sanitize user input before using it in the email headers or body. 

// Sanitize user input before using it in the email headers
$to = filter_var($_POST['to'], FILTER_SANITIZE_EMAIL);
$subject = filter_var($_POST['subject'], FILTER_SANITIZE_STRING);
$message = filter_var($_POST['message'], FILTER_SANITIZE_STRING);

// Send email using sanitized input
mail($to, $subject, $message);

Keywords

PHP mail function email sending SMTP error handling

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