That is quite the wrong way of looking at it. The vulnerability is in a implementation of SSH and not with the language/runtime itself; And it has already been patched. Erlang is a "managed" language and is quite secure compared to others.

You should definitely "sell" Elixir/Erlang/BEAM based languages to your management for a greenfield project; The opportunity is too good to pass up.

Nevertheless, if you would like to learn how to "harden" your Elixir/Erlang system, see the guidelines from the "Security Working Group" of EEF which i have linked to here - https://news.ycombinator.com/item?id=43717633