If there’s a bug in SSH libraries that Canonical ships in Ubuntu, that is their distribution of that library even if they are not the primary authors. Canonical guarantees support for the software it ships, so they are obligated to fix it no matter what. Fixes are upstreamed to the primary author - the author never asked for their software to be included in that distribution so it’s not their problem to fix it for Ubuntu users.

This is a model that solves the problem the author is discussing.