An issue was discovered in Squid 3.x and 4.x through 4.8 when the append_domain setting is used (because the appended characters do not properly interact with hostname length restrictions). Due to incorrect message processing, it can inappropriately redirect traffic to origins it should not be delivered to.
http://www.squid-cache.org/Advisories/SQUID-2019_9.txt
https://bugzilla.suse.com/show_bug.cgi?id=1156328
https://github.com/squid-cache/squid/pull/427
https://lists.debian.org/debian-lts-announce/2019/12/msg00011.html
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html
Source: MITRE
Published: 2019-11-26
Updated: 2020-07-11
Type: CWE-352
Base Score: 5.8
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:N
Impact Score: 4.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 6.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Impact Score: 2.7
Exploitability Score: 2.8
Severity: MEDIUM