In. Not on. The moisture barrier is meant to keep moisture out of the wall cavity. That's why the hotels in the 80's had so many mold issues. They used vinyl wall covering. That basically trapped moisture in the walls. Hopefully your cmu walls have grout in them so plants aren't growing in them. If you have a concrete wall basement, patching is fine. CMU block basements are iffy on patching, let alone putting up a moisture barrier on the wrong side of the wall. If you're gonna be there for only a few years, it probably doesn't matter.