According to a blog-post published by Twitter on Tuesday, the user information that may have been shared without people's permission include country code, details of users' engagement with the ad and information about the ad.
Mainly, information of users who interacted with certain ads concerning mobile applications or ads based on inferences Twitter made about the device that users were using in May and September 2018, has been shared without user permission.
"The data involved stayed within Twitter and did not contain things like passwords, email accounts, etc," the post said.
The company has said that the issue was fixed on August 5 almost a year after the leak happened.
"We know you will want to know if you were personally affected, and how many people in total were involved. We are still conducting our investigation to determine who may have been impacted," the post added.
The micro-blogging site has advised users to check their settings for now.
"You trust us to follow your choices and we failed here. We're sorry this happened, and are taking steps to make sure we don't make a mistake like this again," the post noted.
As of now, further details like data of how many users have been leaked and what could be the repercussion remain undisclosed from Twitter's end.
Especially after the Facebook-Cambridge Analytica scandal broke out that revealed that Facebook compromised personal data of thousands of its users, tech companies including Google and Amazon have come under intense scrutiny in recent years.
( With inputs from IANS )