Home prices are not included in the CPI.
Here's the Bureau of Labor Services Q&A on the topic:
"How the CPI measures price change of Owners’ equivalent rent of primary residence (OER) and Rent of primary residence (Rent)"
https://www.bls.gov/cpi/factsheets/owners-equivalent-rent-an...
Not sure how much that distinction really affects the median person though, if housing (rent) inflation is under control. I suppose people with kids may prefer to buy for long-term consistency, so CPI misses them in a way.