Netty allows request-line validation to be bypassed when a DefaultHttpRequest or DefaultFullHttpRequest is created first and its URI is later changed via setUri(). The constructors reject CRLF and whitespace characters that would break the start-line, but setUri() does not apply the same validation. HttpRequestEncoder and RtspEncoder then write the URI into the request line verbatim. If attacker-controlled input reaches setUri(), this enables CRLF injection and insertion of additional HTTP or RTSP requests, leading to HTTP request smuggling or desynchronization on the HTTP side and request injection on the RTSP side.

This issue is fixed in versions 4.2.13.Final and 4.1.133.Final.