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private browsing: firefox stores cross site cookies

  • 11 replies
  • 0 have this problem
  • 49 views
  • Last reply by mm12345

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When I close a private browsing session and open it again, the given permissions for cross-site cookies are still there and Google remembers my last search results from the last private session (in the suggestions below the search box)!?

When I close a private browsing session and open it again, the given permissions for cross-site cookies are still there and Google remembers my last search results from the last private session (in the suggestions below the search box)!?

All Replies (11)

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I'll add a screenshot now, otherwise it might not be clear

This is displayed when I open a private browsing session although it should be set to zero:

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Cross-site cookies are automatically allowed in some circumstances. You can prevent this by changing Tracking Protection to Custom with Cookies set to block "All cross-site cookies (may cause websites to break)".

Make sure you do not sign into your Google account in the private window.

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That's not the matter: I close the browser -> reopen it -> open a new private session -> go to google.com and its still there!

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These cross-site cookie permissions are automatic and does not indicate cookies are being retained across sessions.

Make sure you close all private windows or quit browser with Command+Q to end the private session.

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Yes, that's right, no cookies are saved, but these cross-page cookie permissions are saved and the idea behind the private mode is that you always start from scratch and not with the last state.

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The permissions are generated automatically from scratch, you can disable cross-site cookies if you are concerned.

While cross-site cookies from trackers are blocked in Firefox by default, a site may signal to the browser that it needs to use them for important functionality. In this case, Firefox will allow a third-party website to use cross-site cookies the first five times (or up to 1% of the number of unique sites you visit in a session, whichever is larger) without prompting you.
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Hi, I know that from your manual, that's not the point. I'm developing a website and if I try to test a certain behaviour, I can only work if I can reproduce a initial state (empty default browser).

And those permissions are not erased after creating a new session!

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You can install Developer Edition for testing an empty default profile.

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Hi, thanks looks nice, I'll try it when I have time. On the other hand, I use incognito mode on Chrome and it works fine there...

I'm interested in where I can reset these cross-page cookie permissions in Firefox?

Modified by mm12345

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Do the cookie permissions not appear on first run in a new profile or Developer Edition?

Do you see any difference if you clear all history (Ctrl+Shift+Del > When > Everything)?

Can you provide a link to a public site with steps to reproduce the issue?

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I've sometimes reproduced it with istockphoto.com, but only when I've opened istockphotos via a Google result and it seems to be necessary to use the session for a while until it set's that permission. (I don't always want to compare you, but it works in Chrome ;)