Does Vegetable Soup Spoil If Left Out Over Night?

You can eat it but, you risk getting very sick. There is a danger zone for food to be left within the temperatures between 40 degrees Fahrenheit and 140 degrees Fahrenheit. For food to be left within this danger zone over 4 hours severely increases the chance of it becoming contaminated and you contracting food poisoning. 

I would not risk food poisoning.

If you leave any food out overnight it will spoil - unless it is sealed in a can.