The plugin does not protect some of its actions against CSRF attacks, allowing an unauthenticated attacker to perform actions on their behalf by tricking a logged in user to submit a crafted request.
patchstack.com/database/vulnerability/woocommerce-follow-up-emails/wordpress-woocommerce-follow-up-emails-plugin-4-9-40-multiple-cross-site-request-forgery-csrf-vulnerability
www.wordfence.com/threat-intel/vulnerabilities/wordpress-plugins/woocommerce-follow-up-emails/woocommerce-follow-up-emails-4940-cross-site-request-forgery