Senator Cory Booker uttered this malaphor on MSNBC’s The Chris Hayes Show. He was talking about the Mueller investigation:
“Um, look, I’m one of those folks that says let’s go where the evidence leads,” he said. “Right now we have a special counsel that is doing a thorough investigation. Let’s not get ahead of our skis. Let’s make sure we support this special counsel’s investigation.” https://www.mediaite.com/tv/chris-hayes-comes-right-out-and-asks-it-in-interview-with-cory-booker-is-trump-a-criminal/
This is a mixture of “out over his skis” (get ahead of yourself) and “ahead of the curve” (leading in something). The two phrases are close in meaning and are both referring to leading in front. It appears the phrase “out over your skis” originated in the finance world. See this article for more on the origin: http://nymag.com/daily/intelligencer/2012/05/where-did-the-phrase-over-his-skis-come-from.html
A big thanks to Frank King for hearing this one and passing it on!