I assume autoexec is referring to the plethora of WebRTC vulnerabilities which have affected browsers, messengers, and any other software which implements WebRTC for client use. Its full implementation is seemingly difficult to get right.
Of course, you're right that this implementation is very small. It's very different than a typical client implementation, I don't share the same concerns. It's also only the WHIP portion of WebRTC, and anyone processing user input through ffmpeg is hopefully compiling a version enabling only the features they use, or at least "--disable-muxer=whip" and others at configure time. Or, you know, you could specify everything explicitly at runtime so ffmpeg won't load features based on variable user input.
Of course, you're right that this implementation is very small. It's very different than a typical client implementation, I don't share the same concerns. It's also only the WHIP portion of WebRTC, and anyone processing user input through ffmpeg is hopefully compiling a version enabling only the features they use, or at least "--disable-muxer=whip" and others at configure time. Or, you know, you could specify everything explicitly at runtime so ffmpeg won't load features based on variable user input.