What are the common pitfalls or mistakes to avoid when working with email headers and content in PHP for sending emails?

One common mistake to avoid when working with email headers and content in PHP for sending emails is not properly sanitizing user input, which can lead to security vulnerabilities such as header injection attacks. To prevent this, always validate and sanitize user input before using it in email headers. 

// Sanitize user input before using it in email headers
$subject = filter_var($_POST['subject'], FILTER_SANITIZE_STRING);
$to = filter_var($_POST['to'], FILTER_SANITIZE_EMAIL);
$headers = "From: sender@example.com\r\n";
$headers .= "Reply-To: sender@example.com\r\n";
$headers .= "MIME-Version: 1.0\r\n";
$headers .= "Content-type: text/html; charset=iso-8859-1\r\n";

// Send the email
mail($to, $subject, $message, $headers);

Keywords

email headers content PHP sending emails mistakes

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