According to Wikipedia, CUNY alumni have never won the Turing Award.
One CCNY alumnus (Jesse Douglas, BA 1936) won the Fields Medal.
12 CUNY Bachelor’s degree recipients, including Hunter and Brooklyn College alumni, have won the Nobel (plus Henry Kissinger, who attended but did not graduate from CCNY). That makes 13 Nobel/Fields winners for the CUNY system during the ~50 year period, which is the quartz.com number (but apparently 10 Nobel/Fields winners for CCNY alone.)
https://en.wikipedia.org/wiki/List_of_Turing_Award_laureates_by_university_affiliation
https://en.wikipedia.org/wiki/List_of_Fields_Medal_winners_by_university_affiliation
https://en.wikipedia.org/wiki/List_of_Nobel_laureates_by_university_affiliation#Other_universities