To be fair, there were a lot of CVEs because part of the sandbox in Java was capabilities-based, and the Achilles' heel of capabilities is that if you can see it, you can use it, and feature factory work has a bad habit of accidentally making things visible by exposing some parent object in an attempt to be helpful.

I did like the permissions inheritance model quite a bit, but the hybrid ACL/capabilities system was always a bit schizophrenic.