Microsoft's Windows Phone 7 still has some teething issues to contend with, one of which was the data leak that has been reported earlier. The Redmond-based company came out to admit that the issue exists, due to a third-party service within the Microsoft mobile OS. A recent investigation by Rafeal Rivera has pinpointed the issue to Yahoo!, prompting Microsoft to admit the issue does lie with the mail provider.
Windows Phone Secrets - Microsoft this evening belatedly admitted that Yahoo! Mail was in fact the data leak culprit in Windows Phone, just hours after Rafael had already proven that to be the problem. Here’s the note from Microsoft, which also includes information about another, semi-unrelated issue for some reason.
If you aren't a Yahoo! mail user, this data leak shouldn't affect you too badly. Even so, Yahoo! will be rolling out an update to rectify this issue. So in the meantime, if you're worried about data leaks, stick to Wi-Fi connectivity. Learn more about the Windows Phone 7 data leak over here.