Google recently updated its Chrome browser for iOS 7 with design tweaks and security fixes, but it appears it has also introduced a bug with incognito mode. British development firm Parallax has discovered that Chrome for iOS 7 no longer keeps incognito tabs secret. If you search using the unified address / search bar in incognito mode and then return to a normal tab and search on Google's mobile website it will show the history from the incognito tab.
The Verge has tested and confirmed that search history is being shared between incognito mode and regular browsing history. Thankfully, the incognito searches will only show up if you search directly from Google's mobile website, and not from the regular unified address / search bar. Either way, it's still a troubling privacy problem for a feature that's designed to keep search history secret. We've reached out to Google for comment on the bug, and we'll update you accordingly.
Update: Sources familiar with the situation say that Google is aware of the issue but is unable to take further action at this time. Google's Chrome help page confirms this, noting that "platform limitation" on iOS make separating the data impossible.
On Chrome for iOS, due to platform limitation regular and incognito tabs share HTML5 local storage, which is typically used by sites to store files on your device (client-side caching) or to provide offline functionality. This means the same sites can always access their data in this storage in both regular and incognito tabs. Incognito tabs will still keep browsing history and cookies separate from regular tabs, which are cleared once those tabs are closed.