darknet subscripts its layer array with an index taken from a configuration file without checking it against the array's length. The array is allocated in src-lib/darknetnetwork.cpp as xcalloc(net.n, sizeof(Darknet::Layer)), sized to exactly the number of layer sections the file declares. The shortcut, scalechannels and sam sections supply that index through their from field and the route section through its layers field, and parseshortcutsection in src-lib/darknetcfg.cpp reads net.layers[index].outputs with no bounds check, which reads past the allocation. The dispatch loop in createnetwork then reuses the same index to assign net.layers[l.index].usebinoutput and net.layers[l.index].keepdeltagpu, writing past the allocation at an offset the file controls, with a fixed one-byte value. Parsing a crafted configuration file is sufficient: the parse runs before any weights file is opened and needs no non-default option, so the result is a reliable crash and a write whose location, though not its value, is chosen by whoever supplied the file.