It will depend on the situation and what is meant, as this sentence is not usually said on its own. It is usually followed with another clause.
There are at least two ways to take this sentence. Forward here could mean "pushy", or "cocky" or "presumptuous" or "assuming". So we could restate it as "I don't mean to assume,(but)..." or "I don't mean to be pushy", or "I don't mean to pry".
The other way its used is in a romantic context:"I don't mean to be forward, but would you like to go to a movie with me sometime?" It's often meant to pay someone a complement without making them think you have a romantic interest - yet it can also imply romantic interest. "I don't mean to be forward, but you have beautiful eyes." To restate it in this context you might say: "Don't take this the wrong way, but you have beautiful eyes".