# CVE-2026-72852: darknet Integer Overflow in Convolutional Layer Buffer Sizing Leads to Heap Buffer Overflow

> An integer overflow in darknet's convolutional layer buffer sizing allows heap buffer overflows when processing crafted configuration files, potentially leading to code execution.

- **Severity:** High 8.5 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 20 Aug 2026
- **Updated:** 24 Sep 2026
- **Also known as:** GHSA-5277-mwh4-q4cc

## What is CVE-2026-72852?

CVE-2026-72852 is a high-severity vulnerability in hank-ai darknet, published on 20 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

hank-ai/darknet sizes a convolutional layer's weight and output heap buffers by multiplying configuration fields taken from a .cfg file in unchecked 32-bit int arithmetic. In src-lib/convolutional_layer.cpp, l.nweights is computed as (c / groups) * n * size * size and l.outputs as l.out_h * l.out_w * l.out_c, and both feed xcalloc directly. A .cfg whose true dimension product exceeds INT_MAX wraps to a small or zero value, so the allocation is undersized; for example width and height of 256 with filters of 65536 gives 2^32, which wraps to 0. forward_convolutional_layer then re-derives the GEMM dimensions with a different operand order, computing k as l.size*l.size*l.c / l.groups where the allocation divided before multiplying, and reads and writes through the undersized buffer. Loading the crafted .cfg for inference or training is sufficient and no valid .weights file is required. The reported proof of concept observed a heap buffer overflow read in gemm_nn_fast under AddressSanitizer and glibc allocator metadata corruption in a release build of the same input, indicating an out-of-bounds write.

Weakness: CWE-787 (Out-of-bounds Write), CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-72852?


## How do I fix CVE-2026-72852?

No fix has been published for CVE-2026-72852 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-72852 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72852 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72852 and fix it if it is affected.

What it is: CVE-2026-72852 is a high-severity vulnerability in hank-ai darknet, published on 20 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72852 exists.

Affected product: hank-ai darknet. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-72852/ (Markdown: https://insights.sbomify.com/CVE-2026-72852/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72852
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72852
- OSV: https://osv.dev/vulnerability/CVE-2026-72852

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-72852/
Summaries are generated and may contain mistakes; the official description above is the record.