Something that is misinformed is based on bad information. Something that is uninformed is based on no information or inadequate information. For example, a webpage on the difference between misinformed and uninformed would be uninformed if it were based on no research or experience, and it would be misinformed if it were based on research drawn from misleading or speculative commentary.
The words are often extended to describe people. A misinformed person is one who has bad information, and an uninformed person is one who has no or inadequate information.