Mozilla just announced a security flaw a couple of days ago. They've got a patch up on their site (addons.mozilla.org). The patch (the page includes directions on how to do it manually) turns off IDN (International Domain Name) functionality, so hopefully you're not going to go to any sites that use non-ASCII characters in their domain names.
You wanted the best, you got... Out of Context Quote of the Week.
"...but that doesn't mean he can't relate an amusing anecdote about the Haiti Kid and one of the Frenchman's testicles." (Hogan's My Dad)
Have you got it set to automatically check for updates? Tools-options-advanced-Software updates If it's a Firefox bug, updates should fix it. If not, try looking for common themes when it does crash - is it whenever you search?
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