Security flaws can be extremely subtle and 200,000 lines of code is a lot to review... Given that there's plausible deniability (we didn't do it intentionally, it was a genuine bug!), if you were them, wouldn't it at least cross your mind to try it?
Also, at some point, if it becomes popular, some sysadmin at a large foreign government agency or company will forget to firewall off a box running it (ignoring that they could also be connecting back directly - automatic updates anyone?)