It turns out there's only one paragraph in the whole Catechism about Islam

Just to refresh memories, it says this:

841 The Church's relationship with the Muslims. "The plan of salvation also includes those who acknowledge the Creator, in the first place amongst whom are the Muslims; these profess to hold the faith of Abraham, and together with us they adore the one, merciful God, mankind's judge on the last day."

Nota bene: it does not say the Muslims are saying and doing exactly the same things as us, or that Jesus is unnecessary for salvation, or that it's okay for Muslim radicals to behead, rape, subjugate, lie and kill, or that we should not evangelize Muslims. How do I know?  Because so far from saying that nobody is a sinner and we should not evangelize, Pope Francis made it his first order of business to call us to evangelize in Evangelii Gaudium, a document that was roundly denounced by the same people who are currently panicking that the Church under evil modernist heretic Pope Francis is not teaching we need to evangelize--people who, themselves, seem to do no evangelization at all while the pope hit the ground running as a global evangelist and has not stopped since he was elected.  Since these people have shown themselves to be epically wrong again and again in their denunciations of Francis, the Magisterium, the Council, and the Church, there is therefore no need to take their word for it and panic that the post-Vatican II Magisterium has abandoned the faith of our fathers and that only angry Reactionaries in comboxes can save the Church from our horrible pope and the Second Vatican Council, as a huge number of responses to this piece would seem to suggest.  Indeed, the Church is simply making the same point that modernist indifferentist heretic Pope St. Gregory VII made, writing to the Muslim Sultan of Bougie in North Africa in 1076:

For there is nothing which Almighty God, who wishes that all men should be saved and that no man should perish, more approves in our conduct than that a man should first love God and then his fellow men ... Most certainly you and we ought to love each other in this way more than other races of men, because we believe and confess one God, albeit in different ways, whom each day we praise and reverence as the creator of all ages and the governor of this world.

(By the way, "Sultan of Bougie" totally sounds like a 70s disco title, or maybe a line from "Rock the Casbah".  But I digress.)

As I discuss here and here the Church's teaching on its relationship with Islam is not fraught with any of the strawmen so many readers spent so much time beating to death.  She's not saying "We're saying the same thing".  She's not saying "Muslims are saved by Islam and Christians are saved by Christ."  She's not denying the need to evangelize or proclaiming "Automatic salvation for all!" She's simply noting--as she does with all other religions and philosophies and schools of thought--that insofar as Muslims affirm certain truths in common with us, they are right.  That's it.  That's all. The entire rest of the Catechism beyond CCC 841 is spent making clear that where Muslims (or anybody else) part ways with Catholic belief and practice, you should go with Catholic belief and practice. 

The problems come when Catholics, angry at Muslims, insist that everything about Islam is wrong and false and wind up telling the Church that she is wrong and false in the process.  Such either/or thinking is, ironically, a deeply Protestant habit of mind and many American Catholics have internalized it.  The Church is perfectly aware of the differences between herself and Islam.  But she begins, as ever, with what can be affirmed.  It's an approach that goes all the way back to Paul on the Areopagus (Act 17) when he affirmed what could be affirmed in common with Athenian pagans and even quoted a couple of their poets to do the job. He was not, thereby, adopting the Athenian pantheon or embracing all of Greek culture without discernment. But many Americans are quite prepared to reject without discernment anything that smells Muslim.  In doing so, they wind up punishing Maronite and other Arabic-speaking Catholics (just for starters) for the "sin" of calling God "Allah" (as they have always done).

Similarly, if we say that Islam is wrong about everything we are saying that it is wrong to affirm that there is one God, the God of Abraham, holy, righteous, merciful and compassionate.  We are saying it is false that  the prophets of the Old Testament are prophets; that prayer, fasting and almsgiving are pious works blessed by God; that Jesus was a prophet; that Mary is to be honored and venerated.  For Muslims say all these things and all these things are true, as far as they go.  The Church, instead of making foolish denunciations of all things Muslim instead does what St. Thomas describes:  She recognizes that grace builds on nature and so takes what is good and true in any culture (even one as depraved as our own culture of warlike abortion-loving polymorphous perversity and greed) and begins proclaiming the gospel there. So, as I say, the Church affirms what can be affirmed in common with any religious tradition.  One need not pretend we agree on all things in order to agree on the things we agree about. But we should listen to CCC 841 and not denounce the Church or call (as some readers did) for banning the Catechism when she challenges our muddy thinking.  Our task is to learn from Her.