Cracking short ciphertexts made by Vigenère cipher
You used the same key for both words so we can start with the obvious: both words start with the same letter and end with the same four letters.  We can process your initial word list, picking out sets of words that match this pattern.  Then just brute force each possible pair within each set until we find one or more pairs.  Work back from the first possible word of a pair to the key, and then forward to the encryption of the second possible word.  Check whether or not it matches "XDBEWUMHNL".

If there is more than one matching pair, then we would need more information.