Yes, there are hosts who can cook a vegan meal and a few are vegans themselves.
That said, there are also hosts who may not be as familiar as others so be sure to be as specific as possible with what you can and cannot eat.
Depending on the level of understanding the host may have there may be slip ups such as forgetting or not knowing to check for meat or seafood extract or using honey.
So it will be helpful to express how flexible you are or on the other hand be extra clear about details that are important to you.