Outdoor box or conduit body?
cringe  

This was a bodge job from the beginning.  Hole unguarded, NM cable coming outside as if Shelter-in-place was over, fitting intended for octagon box misapplied to mount an outside light, etc.  Is the light even rated for outdoors??

(NM-B is not legal nor reliable outside; this could be tripping a GFCI if it was on it just from hot-ground leakage from insulation breakdown. Meanwhile the paper stuffing is wicking water tens of feet down the cable). 

I think a plain old 1/2" conduit body would be perfectly fine as part of a nutritious breakfast - er, proper wiring method.  

I would run up the wall with conduit to your desired light location then fit an appropriate box there.  My preference is a box where the flexible cable to the light exits the bottom of the box with a proper liquidtight strain relief; that way when the liquidtight leaks, water still doesn't get in.  You don't want the conduit to turn into a rain superhighway into your house.  

The only issue is, you can't run NM cable outside, and UF cable won't fit inside conduit (unless you make it stupid-huge).  That limits you to THHN wire, which works great in conduit (use stranded since you'll be splicing to wire nuts at both ends).  You will need to make a transition from NM to THHN somewhere inside the house, and that requires an accessible junction box to do that.