The option to `expand_external_ents`, documented as controlling external entity expansion in XML::Twig does not work. External entities are always expanded, regardless of the option's setting. Upstream bug: https://rt.cpan.org/Public/Bug/Display.html?id=118097
Created perl-XML-Twig tracking bugs for this issue: Affects: fedora-all [bug 1379554]
Statement: Red Hat Product Security has rated this issue as having Moderate security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
Acknowledgments: Name: Doran Moppert (Red Hat Product Security Team)
Upstream released 3.50 that added no_xxe flag that implements the desired behavior, but expand_external_ents flag, subject of this vulnerability, still has no effect. So while XML-Twig >= 3.50 can now be used safely, the reported bug still exists.