Ribery was sent off for a bad tackle on Lyon striker Lisandro Lopez in the 37th minute of Bayern's semi-final first leg against Olympique Lyon last week.
The red card meant he was automatically suspended for the second leg in France, which Bayern won 3-0 to reach the final with ease, and UEFA decided to add two further games to that punishment on Wednesday.
Bayern announced after the ruling that they would appeal.
The final, to be held at Real Madrid's Santiago Bernabeu stadium on May 22, will be against Inter Milan or Barcelona.
Ribery's absence, if confirmed, would come as a significant blow to Bayern, who have reached the Champions League final for the first time since they last won the competition in 2001.
Ribery joined the club in 2007 and made an immediate impact, helping Bayern win a league and cup double in his first season.
The 27-year-old has yet to decide whether he will stay at Bayern or join another major European club at the end of the season.
His sending-off against Lyon came after it emerged he had been quizzed by French police as a witness in a prostitution investigation.
Bayern coach Louis van Gaal said at the time he felt the Ribery tackle was a yellow card offence.
"I thought, watching from the bench, that he stood too long on the opponent's leg," Van Gaal said. "I do not think it was a red card because it was the inner foot and not a foul with full force."
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