It really depends if the two civilizations are competing for resources. In that case, the less advanced civilization is obviously going to have a bad time. Ther

It really depends if the two civilizations are competing for resources. In that case, the less advanced civilization is obviously going to have a bad time. There were cases in human history where human civilizations connected for exploration, trade and research and weren't competing for resources. Not all of those ended badly. Many of those that did end badly, ended badly because of disease. In the case of alien life, the risk of communicable disease would likely be low since any alien life would probably be a significantly different species that microbes would have a hard time jumping between.