Mozilla, who introduced the new tab page in Firefox 13 in the controversies here, NTP shows thumbnails of the most visited sites from the user’s browser history, the Register reports that its user Chris received thumbnails of secure session content in NTP in Firefox 13 , these thumbnails showed sensitive information such as online and banking webmail sessions with account numbers, balances, subject lines, etc.
Mozilla responded to Chris’ questions and they admitted that this behavior is undesirable and promised that they will release a patch for it. This is what Mozilla claimed
“We are aware of the concern and have a fix that will be released in a future version of Firefox. Mozilla remains steadfast in its commitment to user privacy and control. The new tab thumbnail feature in Firefox does not transmit or store personal information outside of the user’s direct control. “
Hide or Disable Firefox New Tab Page
Mozilla says these thumbnails are generated from the user’s browsing history and can be deleted by clearing the browsing history. Users who don’t like this feature can switch to a new blank tab by clicking the square icon in the top right corner of the browser, we’ve covered how to permanently disable it.
Use private browsing mode when the computer is shared or when you are on a public computer
Users are most at risk when they share their computer or browse Firefox public computer with NTP feature enabled, Mozilla suggests users to use private browsing mode in these cases.
After all, Mozilla added NTP feature with thumbnails following Chrome and Opera, AFAIK these browsers didn’t face this problem. We recommend that users clear their browsing history daily using tools like CCleaner to avoid such situations.
Source: The register