1994 Honda Civic Oil in Plugs

I went to change the spark plugs and found that there was oil in one of the spark plug sockets. So I’m asking what this means. Is the problem the head gasket, valve seal, spark plug tube o-rings, or the piston rings?

The oil is coming from a failed O-ring seal at the bottom of the sparkplug well. Purchase a new valve cover gasket set and have it installed. It will come with new O-ring seals.


Sorry for the multiple posts, I had some trouble getting started.