Customer and legal problems put you at great financial risk. E.g. customers get out of paying one way or another and you cannot cover operational costs, you lose customer data and get sued for damages, you screw up on GDPR and get fined, etc.
Bugs in your infrastructure could also cause you to accidentally spin up a shitton of instances far exceeding your operational budget, but that isn't the primary concern.
Bugs in your infrastructure could also cause you to accidentally spin up a shitton of instances far exceeding your operational budget, but that isn't the primary concern.