Accidents happen. I was attacked by an Afghan hound that had been left tied up outside our house by a visiting friend of the family. I was about seven and just walked by it to go into the backyard, and it attacked. It left a scar on my arm, but I don't recall any consequences for the owner. The dog's name was Monster btw- lol. Taught me to be careful around strange dogs, that's for sure.
These days, one call to animal control can fix that. About two moths ago a neighbor of mine had their mastiff outside, unleashed. It was prob about 140lbs and it attacked my golden retriever puppy who at the time was about 25lbs.
She didn't end up being hurt much but I called animal control, which I usually wouldn't have done, but the owner wasn't sorry in the slightest. Long story short, animal control slapped them with $700 in fines and quarantined their dog for 11 days.