i am attacking and i get stunned at vilemaw lair, i have more might but cant get pushed back to base, what happens

Yes — you still get sent back to base. Vilemaw's Lair only stops moves to base; the combat-cleanup recall of attackers is not a move, so it bypasses the restriction.

Also, your higher Might doesn't matter here: a Stunned unit contributes no Might to combat damage (Rule 423.1.b), so no damage is dealt and nothing dies. Since the defender's units are still present, the cleanup recall returns your attacker to base normally (FAQ #7877, #8489).