Is there a known Firefox https exploit

[Jim Byrnes]

Running Ubuntu 12.04 and Firefox 23 both recently updated.

Two things happened this morning to make me wonder if Firefox had been 
compromised.

Logged into my bank and clicked the Checkfree link and got a message 
that the page had temporarily moved and was presented with a link.  I 
called Checkfree and told them and they asked me to read them the url 
and they said it was correct. I logged on paid my bills and logged out.

I then logged on a mutual fund site and saw a message that the page had 
moved.  I closed the tab, cleared Firefox cache and then shut down 
Firefox.  When I restarted it I could log on to both my bank, Checkfee 
and the mutual fund site with no popups. I immediately changed the user 
name and passwords on both sites.


The only thing I did lately that was not normal was I allowed the 
computer to run all night and Firefox was open.  Normally I shut it down 
when I done with it for the day.


I googled for Firefox https exploits but the only thing I found was 
references to the FBI supposedly using Firefox to get Tor users IP 
addresses.

Does this seem like something I should be worried about or report to 
Mozilla?  Or does it just sound like a glitch of some kind?

I just realized while composing this that Checkfree never mentioned the 
temporary link, they just confirmed the url I read was correct.

Regards,  Jim