darknet subscripts its layer array with an index taken from a configuration file without checking it against the array's length

Overview

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/darknet_network.cpp as xcalloc(net.n, sizeof(Darknet::Layer)), sized to exactly the number of layer sections the file declares. The shortcut, scale_channels and sam sections supply that index through their from field and the route section through its layers field, and parse_shortcut_section in src-lib/darknet_cfg.cpp reads net.layers[index].outputs with no bounds check, which reads past the allocation. The dispatch loop in create_network then reuses the same index to assign net.layers[l.index].use_bin_output and net.layers[l.index].keep_delta_gpu, 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.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.