Not a massive concern. As long as the is not oil running on the stanchion its not a problem but your best of getting the forks serviced anyway as your suspension is as important as your tyres for sticking to the road!
You'll need your seals replaceing mostly likely. What age is it?
Just seen in you avatar its a 98... doh. New seals circa £25 delivered if you want to diy it but you will want something to stop the damper rod spinning. Kawak do a tool but i think most people make something up themselves to stop it spinning. Pretty straight forward job to be fair. Oh and replace the oil with new
