An issue was discovered in Varnish Cache before 6.0.6 LTS, 6.1.x and 6.2.x before 6.2.3, and 6.3.x before 6.3.2. It occurs when communication with a TLS termination proxy uses PROXY version 2. There can be an assertion failure and daemon restart, which causes a performance loss.
https://varnish-cache.org/security/VSV00005.html#vsv00005
https://lists.debian.org/debian-lts-announce/2022/11/msg00036.html
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00031.html
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00026.html