import re

# CPF no meio do texto
cpf = 'lorem ipsum CPF 123.456.789-11 blablabla'
print(re.match(r'\b\d{3}\.\d{3}\.\d{3}-\d{2}\b', cpf)) # não encontra
print(re.search(r'\b\d{3}\.\d{3}\.\d{3}-\d{2}\b', cpf)) # encontra