The cms security hole was found more than a decade ago. That was the last major security issue we had. We sent emails to our customers, but never put it on the site or yelled it from the mountain top because it would have brought attention to it by would be hackers. It was probably easy to miss the email since we were sending a lot of emails at the time. We don't send many emails now, but would certainly send one out if we found a security breach.
I think we are more aware of the security issues that exist and what needs to be addressed now. No more issues have been found in more than a decade, so I'm not concerned about it and I use the code on many websites. Anything is possible, but I find it unlikely that something would slip by us now. Of course customers can create their own security holes while developing sites since we give them that power, but I wouldn't lose sleep over it.