www/varnish7 -- Request Smuggling Attack

The Varnish Development Team reports:

A client-side desync vulnerability can be triggered in Varnish Cache and Varnish Enterprise. This vulnerability can be triggered under specific circumstances involving malformed HTTP/1 requests.

An attacker can abuse a flaw in Varnish's handling of chunked transfer encoding which allows certain malformed HTTP/1 requests to exploit improper framing of the message body to smuggle additional requests. Specifically, Varnish incorrectly permits CRLF to be skipped to delimit chunk boundaries.

[source]