The docs for the toolchain he implemented (https://github.com/taviso/rarvmtools) allude to a number of bugs, but doesn't sound (??) like they're related to this vulnerability.
The VM has long since been torn out of the RAR decompressor. These days, when it finds a file containing bytecode, it just hashes the bytecode and matches it against a few hardcoded routines that existed at the time.
Sounds like a good ingredient for a CTF or other puzzle. It could be a small obfuscation where player has to install an ancient version with the VM, or get crazier with a byecode hash collision or abusing undocumented VM quirks.