squid3 is vulnerable to denial of service (DoS). The vulnerability exists when SNMP is enabled which allows a malicious user to crash the application via an SNMP packet.
www.squid-cache.org/Advisories/SQUID-2018_5.txt
www.squid-cache.org/Versions/v5/changesets/squid-5-644131ff1e00c1895d77561f561d29c104ba6b11.patch
github.com/squid-cache/squid/pull/313
lists.debian.org/debian-lts-announce/2018/11/msg00032.html
lists.debian.org/debian-lts-announce/2020/07/msg00009.html
security-tracker.debian.org/tracker/CVE-2018-19132
usn.ubuntu.com/4059-1/