What are the potential issues with using both internal and external links in PHP for a news display?

Potential issue: Mixing internal and external links in PHP for a news display can lead to security vulnerabilities such as cross-site scripting (XSS) attacks if the external links are not properly sanitized. To solve this issue, it is important to validate and sanitize all user-generated content before displaying it on the page.

<?php
// Function to sanitize user input
function sanitize_input($input) {
    return htmlspecialchars($input, ENT_QUOTES, 'UTF-8');
}

// Example usage
$title = sanitize_input($_POST['title']);
$content = sanitize_input($_POST['content']);

echo "<h2>$title</h2>";
echo "<p>$content</p>";
?>