What are potential security risks associated with including external libraries in a PHP script and how can they be mitigated?

Potential security risks associated with including external libraries in a PHP script include the possibility of introducing vulnerabilities present in the library itself, such as code injection or cross-site scripting attacks. To mitigate these risks, it is important to only use reputable libraries from trusted sources, keep the library up to date with security patches, and sanitize inputs and outputs to prevent malicious code execution.

// Example of mitigating security risks by using a reputable library and sanitizing inputs

// Include the external library from a trusted source
require_once 'vendor/autoload.php';

// Sanitize user input before using it
$userInput = $_POST['user_input'];
$cleanInput = htmlspecialchars($userInput);

// Use the sanitized input in your application
echo $cleanInput;