The Portuguese forward shoved the referee after being sent off in Real Madrid’s 3-1 win away against Barcelona at the Camp Nou.
Ronaldo could face lengthy ban for the incident which might be up to 12 matches.
After coming on for Karim Benzema in the second half, Ronaldo gave Madrid a 2-1 lead with a stunning effort but removed his shirt as he celebrates earning a yellow card in the process.
Ronaldo, 32, was shown a second yellow moments later albeit a controversial one for an alleged dive in in the box, prompting him to lose his cool and pushed the center referee Burgos Bengoetxea in the process.
Burgos has included the Cristiano’s incident in his match report writing: “Player: Cristiano Ronaldo Dos Santos Aveiro. Once the red card was shown, the player pushed me slightly in a sign of disagreement.”
The shove could trigger a ban of up to 12 matches under Article 96 of the Spanish federation’s rule book, which deals with “Slight violence towards referees”.
Article 96 applies to players who “grab, push or shake” a referee in a manner that is “slightly violent”, and recommends a suspension of 4-12 matches for the action.