Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus Christ!
While I don't believe the Catholic Church intentionally teaches that human nature was corrupted by Sin in the most literal sense, I am quite sure many Catholics have mistakenly gleamed this interpretation and so it has become a common misconception. I would suppose that the Catholic fathers agree very much with the Orthodox fathers in the sense not that human nature has become corrupted in the concrete, tangible sense, rather since the Fall of Mankind the potentiality and propensity for Sin was introduced in the nature of humankind, indeed the nature of all of Creation. Both human nature and Creation remain perfect in static, but we know by experience of life that life is not static, it is in motion. In the static sense of any given instant moment, human nature is not corrupted in any kind of tangible sense (i.e. inclined towards Sin) rather there is perpetually a potentiality for Sin. Again, sin as explained by other posters above is a momentary separation from God. When we are separated from God by Sin, we experience the pains of Sin. But these pains do not corrupt our nature in some kind of cosmic or eternal sense.
If this were indeed the case, then Baptism would be an instant becoming of perfection rather then a process of gradual perfecting, and further how could explain the fact that we continue to find ourselves in Sin after our Baptisms? If sin was only the consequence of a tangibly corrupted nature, then mechanically it should seem logical that Sin would cease to exist after the Grace of God inherent in the Mystery of Baptism and Holy Communion restores human nature.
However Sin is not a matter of mechanics or logistics, we do not Sin because our human nature was mechanically distorted, marred, or corrupted, rather because the corruption introduced into the Creation and Human nature is not a permanent state of Sin, it is the potentiality to Sin. It is entering Sin into the dice-roll and variable equations of our lives. Before Adam and Eve accepted the invitation to Sin, Sin simply did not exist in human nature. Afterwards, human nature has been forever altered towards this potentiality and propencity to Sin, but we are not all universally condemned in Sins we have yet to commit. That is what I believe folks mistakingly interpret as a "corrupted nature" in that they assume that the effects of Sin were to distort or corrupt in some kind of mechanical or tangible way the nature and reality of being a human being. Sin is not our nature, Sin is simply something we have the ability to do. Our Nature has been altered to allow for Sin to exist and occur, this is true, but Sin has not destroyed our nature. Baptism does not necessarily restore Human nature in a permanent or mechanical sense so much as it infuses through Synergy the Grace of God to OVERCOME our potentiality for Sin. If Sin is a possible variable, Baptism does not remove the variable rather it negates or cross-cancels it out by Grace.
That being said, the Orthodox Fathers then teach that our physical and spiritual nature was not inherently corrupted by Sin, and I feel that in many respects the Catholic Fathers and theologians would agree, its in the popular piety and commoner theology that we find this mix up.
It is like my signature states, "Evil is not a being, it is an accident." St John of Damascus