Ok I'll great you the fact that for security issues trying to contact them privately is probably their preference. But in this case where talking about a bug that causes a machine crash. I don't know but does that even constitute a security flaw? This is more a major software flaw then a security bug. If all bug that makes browsers crash were sent to that security report email, they would be overwhelmed quickly. If it could be used to exploit the machine I'd be with you and would suggest that the bug be reported through the vendors security channel.