message/http

An HTTP/1.1 message as cargo: the request line or status line, headers, and body of one message wrapped inside another, defined in the HTTP/1.1 spec itself — currently RFC 9112, which retired RFC 7230, which retired RFC 2616. Its one famous consumer is the TRACE method, whose response echoes the received request back as message/http; that loop is also why security scanners flag TRACE, since an echoed request can expose cookies to scripts (the cross-site tracing attack). Optional parameters carry the version and whether the enclosed message is a request or response. Outside diagnostics and HTTP test fixtures, you may go a career without meeting one.

Defined by RFC 9112 · IANA registration. Registry facts from the IANA media-types registry via mime-db.