squid3 is vulnerable to HTTP request smuggling. It allows attackers to smuggle HTTP requests through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing whitespace between a header name and a colon.
www.squid-cache.org/Advisories/SQUID-2019_10.txt
www.squid-cache.org/Versions/v4/changesets/squid-4-671ba97abe929156dc4c717ee52ad22fba0f7443.patch
bugzilla.suse.com/show_bug.cgi?id=1156323
github.com/squid-cache/squid/pull/445
lists.debian.org/debian-lts-announce/2019/12/msg00011.html
lists.debian.org/debian-lts-announce/2020/07/msg00009.html
lists.fedoraproject.org/archives/list/[email protected]/message/MTM74TU2BSLT5B3H4F3UDW53672NVLMC/
lists.fedoraproject.org/archives/list/[email protected]/message/UEMOYTMCCFWK5NOXSXEIH5D2VGWVXR67/
security.gentoo.org/glsa/202003-34
usn.ubuntu.com/4213-1/
www.debian.org/security/2020/dsa-4682