The social media site said it discovered it was “inadvertently collecting and sharing iOS location data with one of our trusted partners in certain circumstances.” Twitter said the location data has not been retained and has since been deleted.
The company said: “Specifically, if you used more than one account on Twitter for iOS and opted into using the precise location feature in one account, we may have accidentally collected location data when you were using any other account(s) on that same device for which you had not turned on the precise location feature.
“Separately, we had intended to remove location data from the fields sent to a trusted partner during an advertising process known as real-time bidding.
“This removal of location did not happen as planned. However, we had implemented technical measures to ‘fuzz’ the data shared so that it was no more precise than zip code or city (5km squared).
“This location data could not be used to determine an address or to map your precise movements.
“The partner did not receive data such as your Twitter handle or other unique account IDs that could have compromised your identity on Twitter.
“This means that for people using Twitter for iOS who we inadvertently collected location information from, we may also have shared that information with a trusted advertising partner.”
Twitter confirmed the information was not retained, adding it “only existed in their systems for a short time, and was then deleted as part of their normal process”.
The company said: “We have fixed this problem and are working hard to make sure it does not happen again.
“We have also communicated with the people whose accounts were impacted to let them know the bug has been fixed.
“We invite you to check your privacy settings to make sure you’re only sharing the data you want to with us.
“We’re very sorry this happened. We recognise and appreciate the trust you place in us and are committed to earning that trust every day.”