The CGIHandler class in Python before 2.7.12 does not protect against the HTTP_PROXY variable name clash in a CGI script, which could allow a remote attacker to redirect HTTP requests.
https://security-tracker.debian.org/tracker/CVE-2016-1000110
https://bugzilla.suse.com/show_bug.cgi?id=CVE-2016-1000110
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2016-1000110
http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00040.html