The governing body take a very dim view of anyone being critical of match officials.
Managers, including Arsene Wenger, have been handed lengthy touchline bans for remarks made following European matches.
But a Uefa spokesman confirmed they are not going to take any action against Lennon. He pulled no punches following Mallenco's performance at Parkhead when he failed to take any action against Juve's players as they repeatedly manhandled Celtic players in the penalty box at corner kicks.
The Hoops boss approached Mallenco at half-time to ask him to apply the rules.
But the referee continued to turn a blind eye to the underhand tactics for the rest of the tie.
Afterwards, Lennon said: "I thought he was poor. I thought he was very pro-Juventus. I was disappointed with his performance, to say the least.
"I pointed it out to the referee at half-time in the tunnel area, but he just waved me away.
"I made it clear to the players to flag it up to the referee in the second half, but he ignored our requests.
"They were being fouled, manhandled.
"Every time one of my players tried to move he was held.
"He should have given a penalty on at least two occasions."
Lennon will hope for a much stronger refereeing performance in the second leg of the last 16 tie in Turin on March 6.
With Juve leading 3-0, Celtic's glorious European run appears to set to end that night.
But the Italian side's midfielder, Arturo Vidal, refuses to believe the Hoops' pride will allow them to go out without a fight. He said: "We definitely feel more comfortable with a result like this in the bag, but we're not there yet.
"If we want to make sure of our place in the quarter-finals, we must produce a similar performance in Turin.
"We were up against an aggressive side, but we carried out our plans as we had prepared them. It was much harder than the final score suggests."