I'm new to Adeniums and have a stem issue I can't figure out. The plant was doing well and lots of roots were growing out of the bottom of the pot so I potted it up a size. Used a cacti mixture. Went to check on it today and noticed some oozing from a crack high up on the trunk/stem. Any thoughts/tips on what could be causing this are appreciated.

Your Adenium looks to be in good health. Do you remember this being there when you re potted the plant, assuming not from your comment? With the sap running from wound, it could be that it got damaged. The color of the tissue is fairly dark and definitely worth keeping an eye on it to make sure that this area does not become larger. Coloration could just be the skin healing. With gloves on (to safe guard sap on skin) lightly squeeze the trunk/stem and make sure over the next week or so that it is not becoming soft. This would mean pruning it, if this was to happen.
Rick

Cutting off a healthy stem or leaf will result in almost the same thing ....sap running down the main stem....new sap is generally clear, turning amber brown, and will harden slightly ...... washing the plant off with a spray should remove the darker dried sap

While re-potting....Did you (or pet) by chance: bend, pinch, crush or bump the upper stem against something ?

That "sunken" or "recessed" spot where the sap is coming from, sort of looks like freeze or frost damage ....but would think the damage would be at the tip or top ...

If the area increases in size, or changes appearance ...might want to think about cutting off the stem top, just below that "sunken" or "recessed" spot -

But the outcome is good ....you will actually get more branching and more flowers

Seems like mechanical damage maybe during your repot??

Try to dab some cinnamon on that spot. I would rather further allow that plant to dry off and callus that area. It is like an ugly wound, needs to dry out. If the upper leaves starts to fall off, and that depression spreads, then you may have to do hard pruning, to fully cut the damaged area, and then dab again some cinnamon and allow to heal the area.