Fix for leak at top edge of cleanout when below it you don't have enough pipe to glue an extens

My cleanout has the slightest amount of moisture around the base, you can see "water" on the outside. Fix?

It's only at the bottom-most juncture...so it goes concrete floor, then 2" up from that, then cleanout then about 5" to the next juncture, so you see I don't have much pipe to work with even if it was taken out to fix. What do you do when the leak is just at the top of the cleanout piece, and below that you don't have much pipe to work with (2")???

Fix for leak at top edge of cleanout when below it you don't have enough pipe to glue an extension to raise?chinese theater

If it is a test tee for snaking out the drain then it should be a threaded cap just remove the cap and apply Teflon tape or thread dope w/Teflon in it screw it back in and tighten with a large(18") pipe wrench