An issue was discovered in Jinja2 2.10. The from_string function is prone to Server Side Template Injection (SSTI) where it takes the "source" parameter as a template object, renders it, and then returns it. The attacker can exploit it with {{INJECTION COMMANDS}} in a URI. NOTE: The maintainer and multiple third parties believe that this vulnerability isn't valid because users shouldn't use untrusted templates without sandboxing
https://bugzilla.suse.com/show_bug.cgi?id=1125815
https://bugzilla.redhat.com/show_bug.cgi?id=1677653
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00064.html
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00030.html