That riddle has to be incomplete.
The format for those, unless it's cryptic, is to look at letters that are in the first word but not in the second (or vice-versa) or that are in both, depending on what the clue/line says.
They almost always conclude with a line that gives a clue as to what the answer is as a whole. At present the answer could be fug, ire, sue, hue or hug, but you have absolutely no way to discern which of these it might be.
And I don't think it's any of them.
To me it seems like there's gotta be a clues for a fourth and fifth letter, such as what Guy said, and then a final line relating to the overall answer.
An example of a complete riddle in this format:
My first is in tea but not in leaf
My second is in teapot and also in teeth
My third is in caddy but not in cosy
My fourth is in cup but not in rosy
My fifth is in herbal and also in health
My sixth is in peppermint and always in wealth
My last is in drink, so what can I be?
I’m there in a classroom, do you listen to me?
Gullibility and credulity are considered undesirable qualities in every department of human life -- except religion.