Fixing leaking PVC waste pipe elbow

[MrsSilenceDogood]

Hi,
The PVC waste pipe under my sink is leaking fairly badly from the elbow joint. I am a noob to plumbing, and am looking for a simple explanation regarding how to repair it. For the time being, I put FS-X around the joint. Thanks for the help. See attached photos.
MSD

 

[Madrab]

OK - you have what's called a solvent welded waste pipe run there. Basically the plastic fittings ( 2 swept bends, a straight coupler down into the floor and a length of ABS plastic) and pipe are glued together.

Not sure which one is leaking? The greyish one at the front or the white one at the back? Either way though, the only way to fix it is to take it off and replace, it can't be glued retrospectively or in place really, to do a proper job.

Given it's under a cabinet and heading down through the floor makes it significantly challenging to repair, also given there's very little spare pipe to play with, if it's the swept bend at the front there.