The "My McD's" app in Canada can be used to pre-order food and drink for collection, and stores credit card information for payments.
On some occasions, McDonald's Canada has refused to refund fraudulent transactions and urged users to contact their banks for compensation.
Users of a McDonald's app in Canada are having their accounts commandeered by hackers who are using the accounts to order food for themselves, racking up bills in excess of CAD $2,000.
The scammers appear to quietly access the accounts and then make many regular-sized orders costing around $20 a time.
Victims say they didn't notice the money leaving their accounts, sometimes for weeks.
Over several months, users of the My McD's app say they've been scammed and charged for orders they didn't make, and have posted screenshots of the receipts online.