I heard this yesterday during a conference call.

Problem:
The phrase “up front” introduces a redundancy.

Explanation:
The speaker on the conference call was telling the other call attendees that he wanted to say something before he said something else.

The noun “preface” means a preliminary statement in a book or speech.

So the verb “preface” means to provide a preliminary statement.

And therefore following the verb “preface” with the phrase “up front” introduces a redundancy.

Solution:
“I want to preface this by saying …”