Maybe GitHub being popped for their own insecure by design platform, will cause them to reconsider growth at all costs. I know it's wishful thinking, but the amount of security incidents the past few years because of how actions was designed is wild. It would be great for them to finally recognize this and take ownership.
Can you cite this? It's not YAML execution syntax, surely Github doesn't do it, the only vector I can see is if you put it unquoted into a shell script inside of a GHA yaml.
All you need is user content containing `backticked`, and a github action referencing that via eg "github.event.issue.title" where the shell would normally execute `backticked` as a command (like echo, cat, etc).