Consider OpenBSD patches
There are many patches out there, and very probably some interesting: https://cvsweb.openbsd.org/ports/sysutils/nut/patches/ replicated at https://github.com/openbsd/ports/tree/master/sysutils/nut
(Previously http://www.openbsd.org/cgi-bin/cvsweb/ports/sysutils/nut/patches/ was the place)
One thing that I skipped over in #44 was the suggestion to check permissions:
https://cvsweb.openbsd.org/cgi-bin/cvsweb/ports/sysutils/nut/patches/Attic/patch-drivers_usbhid-ups_c?rev=1.6
(Previously http://www.openbsd.org/cgi-bin/cvsweb/ports/sysutils/nut/patches/patch-drivers_usbhid-ups_c?rev=1.6 was the place)
We should probably generalize this for other OSes as well, or just link to a FAQ entry.