What are the potential security risks associated with using the extract() function in PHP for handling user input data?

Using the `extract()` function in PHP for handling user input data can potentially lead to security risks such as variable injection and overwrite vulnerabilities. To mitigate these risks, it is recommended to avoid using `extract()` with untrusted user input data and instead manually assign variables to specific values.

// Example of how to manually assign variables from user input data
$user_input = $_POST['user_input'];

// Manually assign variables from user input data
$var1 = isset($user_input['var1']) ? $user_input['var1'] : '';
$var2 = isset($user_input['var2']) ? $user_input['var2'] : '';
$var3 = isset($user_input['var3']) ? $user_input['var3'] : '';