Bug - Youtube cookies not being blocked despite 100% blocks in place #2539

I have every variation of youtubes domain set to BLOCK in my cookie settings, show in attachment 1, also block under tools/page-info/permissons as show in attachment 2.

Yet cookies are still being accepted from youtube, shown in attachment 3.

I've deleted cookies.sqlite and cookies.sqlite-wal and it hasn't helped.

Other blocks placed on other websites do work, just not ones placed on youtube.

I previously had this problem a few years back when using firefox - I was unable to block google cookies, now with LW I'm unable to block YT cookies (owned by google).

Is this a bug or is there something baked into firefox by dirtzilla to stop people from blocking google/yt cookies?

Hm, we definitely don't want this. I'll put this on my tab to investigate.

@maltejur wrote in #2539 (comment):

Hm, we definitely don't want this. I'll put this on my tab to investigate.

Cool thanks. To be sure I just checked it out in 2 other profiles - 1 I already have setup and a freshly created one.

I put all the blocks in place, cleared cookies, then navigated through youtube and yet again - still yt cookies are unblockable in both profiles.

It's definitelty 100% impossible to block cookies from youtube, despite what blocks you put in place. I havent checked with google.* domains but the last time I checked (which was a few years ago) - they were unblockable as well..

The fact that this issue is present across multiple profiles including freshly created ones and the fact that blocking other websites cookies works as expected makes me wonder if this is some underhanded BS from dirtzilla - I don't know what else it could be.

Thanks again for this report. I managed to reproduce it, and I also think I found the root cause.

What happens here is that accounts.google.com sets cookies on youtube.com. If you also block accounts.google.com, no cookies should be set anymore.

But still, that this happens is strange, as LibreWolf should block this kind of third-party cookies by default. But as of Bug 1951443, which landed in Firefox 138, it seems ETP strict does not seem to block third-party cookies anymore. We didn't notice this until now. This means we should set network.cookie.cookieBehavior.optInPartitioning ourselves, now that it isn't set by ETP strict anymore.

@maltejur wrote in #2539 (comment):

Thanks again for this report. I managed to reproduce it, and I also think I found the root cause.

What happens here is that accounts.google.com sets cookies on youtube.com. If you also block accounts.google.com, no cookies should be set anymore.

But still, that this happens is strange, as LibreWolf should block this kind of third-party cookies by default. But as of Bug 1951443, which landed in Firefox 138, it seems ETP strict does not seem to block third-party cookies anymore. We didn't notice this until now. This means we should set network.cookie.cookieBehavior.optInPartitioning ourselves, now that it isn't set by ETP strict anymore.

Thanks for investigating, your suggestion worked, now I can't sign in to google so it's not an ideal fix but at least the problems solved, cheers.