An issue was discovered in GNU LibreDWG 0.7 and 0.7.1645. There is a NULL pointer dereference in the function bit_convert_TU at bits.c.
http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00045.html
http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00033.html