Needs options... Rated 2 out of 5 stars

I had a problem with it not giving a cancel button as there is such a thing as cookies that the suspicious site could get a hold of and use my session. I have noticed this with github today and I am unsure if I should trust that they changed as the CN on the old one is every subdomain and the CN on the new one is just github as well the new owner being digicert and 790 days until it expires when the old one was godaddy with 1290 days left. You would expect that they wouldn't change until it reaches the end of the certificate as there would be no reason so I am guessing the new one is fake and I am unable to push cancel to stop it from loading...

This review is for a previous version of the add-on (1.8.3). 

You'll have to file a bug report with Mozilla...

There is no Firefox API that allows us to prevent a web page from
being loaded. All we can do and intend to do is to add a "Reject"
button which keeps the new certificate from being stored as "seen
before". This obviously doesn't solve anything and the user is
still in charge of closing the window to the bogus website herself.
You'll have to file a bug report with Mozilla if you'd like to see
this kind of behaviour from CertPatrol.