I suppose it kind of depends. I agree with the curl team here that this is a case of garbage in/garbage out, but I can imagine this going wrong with a binary pr

I suppose it kind of depends. I agree with the curl team here that this is a case of garbage in/garbage out, but I can imagine this going wrong with a binary protocol like HTTP2 on the front and a text protocol like HTTP 1.1 behind a reverse proxy. The \r\n will make it to the proxy as a separate header, but will be turned into two headers on the upstream. That said, this would be a (reverse) proxy vulnerability, not one in curl.