1. A method for predicting downhole casing leaks of hotspots, comprising: obtaining, by a data processing apparatus, raw electromagnetic (EM) corrosion data for a hotspot, wherein the raw EM corrosion data includes a metal thickness loss value for the hotspot; determining, by the data processing apparatus, a corrosion parameter based on the raw EM corrosion data, wherein the corrosion parameter includes at least one of an average remaining barrier, a corrosion rate, or an expected life; generating, by the data processing apparatus, a probability distribution curve for the corrosion parameter; generating, by the data processing apparatus, a corrosion severity classification matrix based on the probability distribution curve, wherein the corrosion severity classification matrix includes a plurality of corrosion severity classes and cutoff values for each of the plurality of corrosion severity classes; and assigning, by the data processing apparatus, the hotspot into one of the plurality of corrosion severity classes based on the corrosion severity classification matrix and the corrosion parameter of the hotspot.