Missing authorization in the Address Delete controller in Mageplaza GDPR for Magento 2 (mageplaza/module-gdpr) through 4.2.9 allows remote unauthenticated attackers to delete any customer's saved address, and to erase all stored addresses by iterating the address id, via a GET request to /customer/address/delete/id/{id}. The controller extends the legacy Action class instead of AbstractAccount, so no authentication, ownership or form key check is enforced.