What potential issues can arise when handling form submissions in PHP, as seen in the provided code snippets?

One potential issue when handling form submissions in PHP is the lack of validation and sanitization of user input, which can lead to security vulnerabilities such as SQL injection or cross-site scripting attacks. To solve this issue, always validate and sanitize user input before processing or storing it in a database.

// Validate and sanitize user input before processing
$name = isset($_POST['name']) ? htmlspecialchars($_POST['name']) : '';
$email = isset($_POST['email']) ? filter_var($_POST['email'], FILTER_SANITIZE_EMAIL) : '';
$message = isset($_POST['message']) ? htmlspecialchars($_POST['message']) : '';