In Varnish Cache before 6.6.2 and 7.x before 7.0.2, Varnish Cache 6.0 LTS before 6.0.10, and and Varnish Enterprise (Cache Plus) 4.1.x before 4.1.11r6 and 6.0.x before 6.0.9r4, request smuggling can occur for HTTP/1 connections.
https://www.debian.org/security/2022/dsa-5088
https://varnish-cache.org/security/VSV00008.html
https://lists.debian.org/debian-lts-announce/2022/02/msg00014.html