Squid is vulnerable to denial of service. The issue trigger is a header that can be expected to exist in HTTP traffic without any malicious intent by the server.
www.squid-cache.org/Versions/v4/changesets/squid-4-1e05a85bd28c22c9ca5d3ac9f5e86d6269ec0a8c.patch
www.squid-cache.org/Versions/v5/changesets/squid-5-8af775ed98bfd610f9ce762fe177e01b2675588c.patch
github.com/squid-cache/squid/security/advisories/GHSA-572g-rvwr-6c7f
lists.debian.org/debian-lts-announce/2021/06/msg00014.html
lists.fedoraproject.org/archives/list/[email protected]/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/
lists.fedoraproject.org/archives/list/[email protected]/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/
security-tracker.debian.org/tracker/CVE-2021-33620