CVE-2026-81334: darknet through 6.0 Out-of-Bounds Read and Write via Unchecked Layer Index in .cfg Parser
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.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
Any deployment that parses configuration files from untrusted or insufficiently trusted sources is exposed. Exploitation occurs while the configuration is parsed, before a weights file is opened.
Does exploitation require special options or prior access?
No non-default option is required, and the attacker only needs to supply a crafted configuration file for parsing. User interaction is required according to the supplied severity vector.
Which configuration fields can carry the malicious index?
The from field in shortcut, scale_channels, and sam sections can supply the index. The layers field in a route section can also supply it.
What happens if a malicious configuration is parsed?
The parser can read beyond the allocated layer array and the network-creation dispatch loop can write beyond it. This provides a reliable crash and an out-of-bounds one-byte write at a location controlled by the configuration author, although the written value is fixed.