The former Western Force player was sent to the sin-bin in the first half for a high hit on the Crusaders' Israel Dagg, who was taken from the field and failed a head injury assessment.
The citing commissioner believed Peni should have been shown a red card for the incident upon reviewing the match.
The nature of the offence is a player must not tackle an opponent dangerously.
Peni will face the SANZAAR Foul Play Review Committee on Monday.
The Brumbies lost the game 21-8 and slumped to fourth in the Australian conference with a 3-6 record.
It was nowhere near the one-sided affair many had predicted when experienced stars David Pocock and Christian Lealiifano were ruled out for the Canberra team.
But the Christchurch-based franchise secured their seventh win of the season with a dominant 15-minute period in the first half, converting two tries when Brumbies winger Chance Peni was in the sin-bin.
Dagg's replacement Manasa Mataele ended up being the man to sink the home team, having an immediate impact by running over for two tries in only five minutes to blow the advantage out to 16 points.
The New Zealand conference leaders barely looked like scoring again after that, but it mattered little as their defence reigned supreme as neither side added to the halftime score.
Despite dominating possession in the second half and having numerous opportunities to storm back into the match, the Brumbies couldn't get through the Crusaders' brick wall.
Even when key pair Ryan Crotty and Scott Barrett were in the sin-bin at the same time, the Brumbies were unable to capitalise on the Crusaders being two men down.
The Brumbies stormed out of the blocks with a sensational try by Henry Speight in the corner in the second minute, but home crowd hopes were wiped out when outside centre Tim Bateman scored for the Crusaders in the 17th minute.
The result ensured New Zealand Super Rugby teams' strangehold over their Australian opponents extended to 36-straight victories since May 2016.