# CVE-2026-44512: ONNX: Null Pointer Dereference in Upsample Version Converter Adapter (Zero Inputs)

> An attacker can cause a denial of service by providing a malicious ONNX model with zero inputs to the version converter.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **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:** Yes
- **Published:** 8 Jul 2026
- **Updated:** 9 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-44512, ECHO-584a-b2f6-d7a8, GHSA-hwpq-hmq9-wj77, PYSEC-2026-2689, UBUNTU-CVE-2026-44512

## What is CVE-2026-44512?

CVE-2026-44512 is a medium-severity vulnerability in onnx, published on 8 Jul 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

Open Neural Network Exchange (ONNX) is an open standard for machine learning interoperability. From 1.9.0 before 1.22.0, onnx.version_converter.convert_version() can dereference a null pointer in Upsample_6_7::adapt_upsample_6_7() in onnx/version_converter/adapters/upsample_6_7.h when processing an untrusted model with an Upsample node that has zero inputs, causing an unrecoverable denial of service. This issue is fixed in version 1.22.0.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-44512?

3 open source packages ship an affected version, including onnx. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `onnx` | PyPI | From 1.9.0 | 1.22.0 |
| `onnx` | PyPI | From 1.9.0 | 1.22.0 |
| `onnx` | PyPI | From 1.9.0 | 1.22.0 |

Products: Linuxfoundation Onnx.

## How do I fix CVE-2026-44512?

Upgrade onnx to 1.22.0 or later.

## Is CVE-2026-44512 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44512 exists.

## Other vulnerabilities in onnx

- [CVE-2025-51480](https://insights.sbomify.com/CVE-2025-51480/): Path traversal in n/a (high 8.8)
- [CVE-2024-5187](https://insights.sbomify.com/CVE-2024-5187/): Arbitrary File Overwrite in download_model_with_test_data in onnx/onnx (high 8.8)
- [CVE-2026-27489](https://insights.sbomify.com/CVE-2026-27489/): ONNX: Path Traversal via Symlink (high 8.7)
- [CVE-2026-34445](https://insights.sbomify.com/CVE-2026-34445/): ONNX: Malicious ONNX models can crash servers by exploiting unprotected object settings. (high 8.6)
- [CVE-2026-28500](https://insights.sbomify.com/CVE-2026-28500/): ONNX Untrusted Model Repository Warnings Suppressed by silent=True in onnx.hub.load() — Silent Supply-Chain Attack (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44512 and fix it if it is affected.

What it is: CVE-2026-44512 is a medium-severity vulnerability in onnx, published on 8 Jul 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-2026-44512 exists.

Affected packages and fixed versions:
- onnx (PyPI): affected from 1.9.0; fixed in 1.22.0
- onnx (PyPI): affected from 1.9.0; fixed in 1.22.0
- onnx (PyPI): affected from 1.9.0; fixed in 1.22.0

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-2026-44512/ (Markdown: https://insights.sbomify.com/CVE-2026-44512/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44512
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44512
- OSV: https://osv.dev/vulnerability/CVE-2026-44512

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44512/
Summaries are generated and may contain mistakes; the official description above is the record.