The cachemgr.cgi web module of Squid through 4.7 has XSS via the user_name or auth parameter.
https://www.debian.org/security/2019/dsa-4507
https://usn.ubuntu.com/4059-2/
https://usn.ubuntu.com/4059-1/
https://seclists.org/bugtraq/2019/Aug/42
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html
https://lists.debian.org/debian-lts-announce/2019/07/msg00006.html
https://github.com/squid-cache/squid/pull/429
https://bugs.squid-cache.org/show_bug.cgi?id=4957
https://access.redhat.com/errata/RHSA-2019:3476
http://www.securityfocus.com/bid/109095
http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00056.html
http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00053.html
http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00067.html