Boy if they only used Rust, then these curl commands that no one would ever enter would have been memory safe.
Seriously I can't understand the threat model here.
I think the realistic attack model here is:
1. SoHo router that has a public accessible endpoint that takes inputs boiling down to "safe" cURL flags;
2. Those flags can actually induce memory corruption;
3. An attacker is able to execute arbitrary remote code in the context of the cURL subprocess through a payload packed into the "safe" flag.