¡Hola! Coming from #sumo where we've got: https://twitter.com/ya_f/status/924743492882063360/ https://twitter.com/Xabi_Goro/status/923100245327740928/ https://support.mozilla.org/questions/1178989/ It would be helpful if Firefox could detect this kind of thing and "self heal" Some MSFT KB articles that might be handy: https://support.microsoft.com/help/234749/ https://support.microsoft.com/help/3083806/ ¡Gracias! Alex

The screenshots in the twitter links look like examples of bug 1382260, bug 1404919 or similar (though AFAICS they don't mention the OS involved, which is a crucial piece of info). If the issues are still occurring on Firefox 57 and later, there may be additional font manager scenarios we need to handle; to understand better, we'd need more details of what font utilities are involved for the affected users.

Jonathan, we have examples from three operating systems, would you like separate bugs for each?

Alex, I think the next steps are asking the users to update to 57.

(In reply to guigs [guigs] PST (please needinfo me!) from comment #2) > Jonathan, we have examples from three operating systems, would you like > separate bugs for each? Yes please; if this is sandboxing-related (as I suspect), it's most likely highly platform-specific. To check whether the sandbox is the issue, people could try setting security.sandbox.content.level down to 1 (and restarting Firefox), and see whether the problems persist.

¡Hola guigs! FWIW I've tweeted at the users to come please check this bug: https://twitter.com/alex_mayorga/status/928980892889919488 https://twitter.com/alex_mayorga/status/928981429786001408 The SuMo reporter is yet to reply back if the MSFT KB fix helped. ¡Gracias! Alex

¡Hola Jonathan! Would uplifting the patch for https://bugzilla.mozilla.org/show_bug.cgi?id=1416229 help here? This seems to also affect about:privatebrowsing per https://support.cdn.mozilla.net/media/uploads/images/2017-11-06-10-49-43-8e616f.png ¡Gracias! Alex

(In reply to alex_mayorga from comment #6) > ¡Hola Jonathan! > > Would uplifting the patch for > https://bugzilla.mozilla.org/show_bug.cgi?id=1416229 help here? Bug 1416229 was a problem with the initial version of bug 1412090, and was immediately fixed by backing that out. So that issue only existed on Nightly for one or two days. What would probably help here (for Linux users; not for Windows or macOS folk, as the implementations of font management and of sandboxing are separate, platform-specific code) is to uplift the re-landed version of bug 1412090. I have requested beta uplift there. > > This seems to also affect about:privatebrowsing per > https://support.cdn.mozilla.net/media/uploads/images/2017-11-06-10-49-43- > 8e616f.png Exactly what pages are affected will depend on the specific locally-installed fonts on the user's system; in principle, any page that relies on system-installed fonts could be affected. (Webfont resources loaded via @font-face are immune.)

¡Hola Jonathan! Any hopes for a fix? Per https://support.mozilla.org/questions/1203722 this seems to still be a thing in 57-58. ¡Gracias! Alex

That looks like a macOS user, in which case I guess this should be fixed by bug 1393259.