Popular fitness-tracking app Runkeeper has revealed it has been keeping tabs on users when they didn't know it, but it was all down to a bug within the app.
A blog post by Runkeeper states the bug was identified in a third-party advertising service included in the app and a new update to the app has taken the service out.
Runkeeper wrote, "Like other Android apps, when the Runkeeper app is in the background, it can be awakened by the device when certain events occur (like when the device receives a Runkeeper push notification).
"When such events awakened the app, the bug inadvertently caused the app to send location data to the third-party service."
The tracking problem was brought to Runkeeper's attention by the Norwegian consumer watchdog, which made a complaint that customer's privacy was being invaded.
Even though the bug only affected the Android app, Runkeeper has also decided to pull the third-party service from the iOS version of the app as well.
The Norwegian consumer authority also expects Runkeeper to ensure the third-party ad network deleted all the illegally collected location data from their servers.
Mistakes like this highlight how we never know exactly what our information our apps are collecting at all times.
This is a very rare scenario, but you trust your apps to only work when you ask them to and it's disappointing to find an app with 45 million users has been through this issue.