A Denial Of Service vulnerability in MiniUPnP MiniUPnPd through 2.1 exists due to a NULL pointer dereference in GetOutboundPinholeTimeout in upnpsoap.c for int_port.
https://www.vdoo.com/blog/security-issues-discovered-in-miniupnp
https://usn.ubuntu.com/4542-1/
https://lists.debian.org/debian-lts-announce/2019/05/msg00045.html
https://github.com/miniupnp/miniupnp/commit/86030db849260dd8fb2ed975b9890aef1b62b692
https://github.com/miniupnp/miniupnp/commit/13585f15c7f7dc28bbbba1661efb280d530d114c