1939928 - Anti-fingerprinting makes Firefox unusable for certain languages

Status: UNCONFIRMED

(Core :: Privacy: Anti-Tracking, defect, P3)

Description

[Ambrose Li]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:131.0) Gecko/20100101 Firefox/131.0

Steps to reproduce:

Nothing (all settings left at default)

Actual results:

When using private browsing,

1. On YouTube, a video from a Korean TV station have almost all Korean characters replaced by squares
2. On Cantonese Wikipedia, locally installed fonts are not honoured, so many characters are missing.

Some of these non-Latin sites don’t work even when in a non-private container tab.

Expected results:

There needs to be a way to mark certain fonts as always allowed. (This is W3C’s position as far as I understand.) Also, the current settings page is misleading; it does not mention the fact that anti-fingerprinting means font blocking. “Font blocking” MUST be explicitly stated because this is a no-no for users of small resource languages and/or users on slow connections.

The settings page says standard security should not affect normal sites. This might be true if you use a European language but I have run into so many problems I have turned it off even for private browsing; it makes Firefox completely unusable.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Layout: Text and Fonts' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Emma Zühlcke [:emz]]

Could you please provide links to pages where you run into this issue?

Comment 3

[Ambrose Li]

Attachment: Screen shot of page in Korean

For Korean, I’ll have to create a new profile and then find the page (for some reason I did not record this URL); a screen shot is attached.

For Cantonese, Cantonese Wikipedia is zh-yue.wikipedia.org (no relation to zh.wikipedia.org)

Comment 4

[Ambrose Li]

Korean example: https://www.youtube.com/watch?v=NMvg-lPf2OM (checked with new profile)

Comment 5

[Ambrose Li]

Attachment: Example from Wikkipedia

Cantonese example (also applies to Chinese in general): https://zh-yue.wikipedia.org/wiki/%E5%85%83%E7%B4%A0%E9%80%B1%E6%9C%9F%E8%A1%A8

Note: Cantonese Wikipedia has a page for recommended fonts: https://zh-yue.wikipedia.org/wiki/Wikipedia:Unicode%E6%93%B4%E5%85%85%E5%94%90%E5%AD%97
All recommended fonts would be blocked by Firefox’s anti-fingerprinting algorithms.

The above list also references a page on the Chinese Wikipedia, whose page title is also blocked by Firefox: https://zh.wikipedia.org/wiki/%F0%A8%A7%80

Note: For CJK, most charaters would show (albeit in the wrong font), but some characters will not show. You will never know when you’ll hit a character that’s blocked by Firefox, and this could be on a page you cannot reload (e.g., if you reload you’ll lose the session, etc.).