Malen nodded hosts Villa in front from a Youri Tielemans cross but was struck on the head while celebrating by an object thrown from the section housing the away supporters.
The Dutch international suffered a small cut but shrugged off the incident and doubled Villa’s lead after being teed up by Morgan Rogers just before half-time.
Young Boys fans clashed with police after the goal and captain Loris Benito went over and pleaded with them to settle down as the match was briefly interrupted.
Joel Monteiro pulled one back in the 90th minute for Young Boys with a thumping finish but Villa secured a fourth win in five games to leave them trailing only Lyon and Midtjylland on goal difference.
Villa are on a run of 10 wins in 12 matches in all competitions after a five-match winless run to start the Premier League season.
“I think we’ve turned it around quite well and we just have to keep this form and stay humble and work hard,” Malen told TNT Sports, insisting he was “fine” after being hit by a plastic cup.
Ryan Yates, Arnaud Kalimuendo and Nikola Milenkovic scored as Forest cruised to a 3-0 win over Malmo at the City Ground in a repeat of the 1979 European Cup final.
Yates curled Forest in front before French striker Kalimuendo turned in from close range to net his first goal for the club.
Milenkovic sealed a second win in five European outings for Forest on the hour as Sean Dyche’s team climbed into 16th place on eight points.
“It is unbelievable. These nights at the City Ground in Europe, we have to cherish them. They are just so special,” Yates said. “We knew if we performed to what we know we can, we would get the result.”
Lyon took over top spot with a 6-0 rout of Maccabi Tel Aviv in Serbia as captain Corentin Tolisso grabbed a hat-trick. Abner Vinicius, Moussa Niakhate and Adam Karabec were also on the scoresheet for the visitors.
Danish side Midtjylland lost their perfect record in the league phase after going down 2-1 away to Serie A leaders Roma. (AFP)
