At least 3 different groups have been leveraging the NSA EternalBlue exploit, what’s went wrong?

At least 3 different groups have been leveraging the NSA EternalBlue exploit weeks before the WannaCry attacks, here’s the evidence. In the last days, security experts discovered numerous attacks that have been leveraging the same EternalBlue exploit used by the notorious WannaCry ransomware .

Source: At least 3 different groups have been leveraging the NSA EternalBlue exploit, what’s went wrong?