It is possible for canned soup to go "bad" if it is not stored properly. Canned items are best stored in a cool, dry place out of direct sunlight and should be used prior to the expiration date.
There are several signs that indicate that canned food is spoiled. The exterior of the can may be dented or leaking, or the lid may be bulging. The food inside the can may appear moldy or discolored, or it may have an unusual odor. Liquid may spurt out when the can is opened. Food that is suspected to be spoiled should not be consumed and should be discarded immediately.