An issue was discovered in Varnish Cache before 6.0.4 LTS, and 6.1.x and 6.2.x before 6.2.1. An HTTP/1 parsing failure allows a remote attacker to trigger an assert by sending crafted HTTP/1 requests. The assert will cause an automatic restart with a clean cache, which makes it a Denial of Service attack.
https://www.debian.org/security/2019/dsa-4514
https://varnish-cache.org/security/VSV00003.html
https://seclists.org/bugtraq/2019/Sep/5
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00089.html
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00069.html