Is 95 minutes enough transfer time at Newark (ewr) incoming at terminal B from Cancun, outgoing from terminal B for Oslo?
Flying United all the way.
The physical movement between the two terminals doesn't require much time, maybe 10 minutes. The most time-consuming part of what you're doing is clearing U.S. Customs and Immigration. The time required for that step varies widely, but can take several hours.
If you're a U.S. Citizen or resident, plan on having 2-3 hours, just to be on the safe side. Add an hour if you're a citizen of another country. You'll need to pick up your luggage and re-check it after passing through U.S. Customs and Immigration. The passport control checkpoint by itself can require over an hour in line (but the passport check itself is short, even shorter if you're a U.S. Citizen).
The 95 minutes you have between your connections is probably too short, especially if you're traveling at a busy time.