GNU LibreDWG 0.9.3.2564 has a NULL pointer dereference in get_next_owned_entity in dwg.c.
https://github.com/LibreDWG/libredwg/issues/179#issuecomment-570447190
http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00052.html
http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00046.html