The company announced on Thursday that even though it has since fixed the issue, "As a precaution, consider changing your password on all services where you've used this password,".
Chief executive Jack Dorsey tweeted:
He also said that "it's important for us to be open about this internal defect".
It is to be noted that Twitter's chief technology officer Parag Agrawal had initially said the company did not have to reveal the information but believed it was the "right thing to do".
Twitter also assured that there is no evidence passwords have been leaked or misused, it is urging its users to update their passwords.
The passwords on Twitter are protected via a process called hashing, which shows random characters in place of the actual passwords. But the detected bug stored the passwords in their original plain-text form to an "internal log."