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Making moves
Status: New idea

So to say, this whole deal of SEC_ERROR_EXPIRED_CERTIFICATE blocking access to the entire page is really dumb, and needs to be given the option to allow a particular exception or another through, without allowing or denying all.

For an example, I went to access a site today whose certificate expired in LESS than twelve hours, and in an ideal world that would be given an exception.

I'm pretty sure you could at least do like Microsoft Edge and allow us to continue to the page:



Status changed to: New idea
Community Manager
Community Manager

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For an expired certificate -- here's a test page for quick reference: -- you should see an Advanced... button on the error page. Clicking that button provides more detailed information about the problem and a button allowing you to proceed to the page. If you do that, Firefox will save an exception for the certificate so it continues to be trusted on future visits (assuming it's not a private window).

Making moves

Firefox currently does not allow an exception for expired certificate when HSTS is used. This entirely precludes user from making a decision to accept risk and proceed anyway.

For example, today certificate expired among many other supporting websites due to broken automated renewed certificate propagation to related webservers. Until process is fixed on the server side there is currently no way to access those pages with Firefox.

Upon closer inspection of HSTS RFC I can see that it specifically declares No User Recourse policy in

   Failing secure connection establishment on any warnings or errors
   (per Section 8.4 ("Errors in Secure Transport Establishment")) should
   be done with "no user recourse".  This means that the user should not
   be presented with a dialog giving her the option to proceed.  Rather,
   it should be treated similarly to a server error where there is
   nothing further the user can do with respect to interacting with the
   target web application, other than wait and retry.
New member

Hopefully this is a bug rather than a feature that was intentionally implemented.

If it's a bug, I look forward to it being fixed.

If it's a "feature", it's absurd. The way it used to work was sufficiently obscure that it was impossible to bypass the warning accidentally. It's my computer, it's my risk. (And the certificate for the site that I will now have to access in Bing et al w/o my bookmarks etc handy just expired a day or two ago and I'm quite willing to take the risk). On the upside, this will force me to overcome inertia and try other browsers that seem to be far more popular now than FF has become!

New member

Yeah, don't treat us like babies, Mozilla. We are entitled to take risks with our own security. You need to allow us to bypass this thing.

Making moves

HSTS specification declares no user recourse policy as I highlighted above. There will not be a way to accept invalid certificate.

Strict transport security is not a default and enabled by website owner.

New member

Yes, you have to use other browsers that are more user-oriented in these cases.

I have never had any issues opening sites with expired certificate and strict transport security.

If I understand what I am doing, then why do I need these barriers?

New member

We really do need a feature or option for accessing site like these.

In my case the web-interface of an appliance is using Let's Encrypt and does not auto-renew in time, rending me unable to access and renew the Certificate.

New member

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