The net/http package's Request.ParseMultipartForm method starts writing to temporary files once the request body size surpasses the given "maxMemory" limit. It was possible for an attacker to generate a multipart request crafted such that the server ran out of file descriptors.
Created golang tracking bugs for this issue:
Affects: fedora-all [bug 1401987]
Affects: epel-all [bug 1401988]
Upstream bug with more details: