Inband signalling is such a terrible idea and is so hard to get right. Here's the next step: try screwing up how you write headers. Use line wrapping and commen

Inband signalling is such a terrible idea and is so hard to get right. Here's the next step: try screwing up how you write headers. Use line wrapping and comments[1], or mix up crlf with just cr or lf. Very possible you'll make one proxy ignore your malicious header, but have the next HTTP software take it. This type of attack can be called "confused deputy". This same issue exists on many VoIP networks as they share the same broken parsing ideas (in SIP). 1: HTTP allows you to line wrap headers and add comments. It's stupidly bizarre. It comes from the 70s or 60s where you wouldn't have a client program, so human-formatted headers weren't just a debug benefit, but a necessary requirement. The IETF can be rather clueless, so they blindly copy these terrible ideas into new protocols, like HTTP and SIP.