In Captain Marvel it would appear as if Carol can break the fourth wall. First, we have the "knowing smile" she gives after Stan Lee's cameo in the film which directors Anna Boden and Ryan Fleck acknowledge as her breaking the fourth wall without stating in those terms.
At one point, her eyes fall upon an elderly man conspicuously reading a _Mallrats _script. It's Stan Lee, practicing his lines for his cameo in that other movie. "Trust me, true believer," he mutters to himself. You can watch that entire Mallrats scene below:
The Captain Marvel scene was originally written by directors Anna Boden and Ryan Fleck as just another fun, funny appearance by the comics legend. But after his passing in November, the filmmakers felt compelled to update the sequence to acknowledge the "gravitas" of the moment.
"Instead of just the pure laugh we had, we had a little bit of a smile from Captain Marvel in response to it, and she kind of breaks character for a moment," Boden told me during an interview in Los Angeles last month. "I think it reflects a little bit of what the audience is feeling, and we allowed that to happen."
In the finished cut of Captain Marvel, Vers' gaze lingers on him for a few moments and she smiles to herself, before moving on with the rest of her quest. At the screening I attended, the audience definitely appreciated the homage – there were sighs, moans, and even a smattering of applause.
Later in the film we then have a scene where Carol is trying out new suit designs where each design is probably a reference to a previous comic version of the character. The last one she stops on is the white and green suit of Mar-Vell and Carol appears to give a "knowing look" before moving on to pick the final design.
In both cases she doesn't have to have broken the fourth wall in universe for the scenes to still make sense. The first "break" could be read as Vers breaking her "angry Vers must catch evil Skrull" character and smiling at "an old man" practising lines on a train rather than her actually breaking the fourth wall. And the second could simply be her "liking the design" rather than acknowledging the reference.
Regarding both of these it would appear that she might be able to break the fourth wall. However, I would like to know if there is any official statement on this in that if the character actually can or if it was more "just a bit of fun". If she can break the fourth wall has this ever been shown in the comics?
Can Captain Marvel break the fourth wall?
I am mainly looking for answers related to the MCU but answers sourced from the comics are perfectly acceptable too.