Firefox To Block Third Party Cookies From Version 22 Onwards

Good news for web surfers worried about 3rd party cookies – Firefox will be blocking them in the future. Just don’t hold your breath though – as Firefox 19 was only released a few days ago you’ll probably have to wait until the end of June to get version 22.


The new patch will enable Firefox to allow cookies on sites that users visit directly but will block third party cookies if the user has never visited that cookie’s home site. Such blocking will likely affect web advertisers who place cookies to track surfers across the web and to collect information about them in order to serve more targeted ads.

The system to be implemented in Firefox 22 will differentiate Mozilla’s browser from Chrome, which currently allows all cookies, and Internet Explorer which blocks some, but not all, third party cookies.

“How does Firefox’s new policy compare to the other major browsers?

Chrome – Allows all cookies.

Internet Explorer – Cookie permissions vary by P3P compact policy. In practice, almost all third-party tracking cookies are allowed.

Safari – First-party content has cookie permissions. Third-party content only has cookie permissions if the content already has at least one cookie set.

In short, the new Firefox policy is a slightly relaxed version of the Safari policy.”
Jonathan Mayer, Web Policy

The patch, contributed by Jonathan Mayer (see WEb Policy link above), will lead to the automatic blocking of such cookies. Users can currently achieve the same result with Firefox manually.

About Lee Munson

Lee's non-technical background allows him to write about internet security in a clear way that is understandable to both IT professionals and people just like you who need simple answers to your security questions.

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