Is CVE-2026-34447 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-34447 being exploited in the wild.

How severe is CVE-2026-34447?

Medium severity, with a CVSS score of 5.5, published 1 April 2026.

Which products and versions are affected?

onnx (PyPI) < 1.21.0, ECOSYSTEM:introduced=0,fixed=1.21.0.

Is there a fix for CVE-2026-34447?

Yes. onnx (PyPI): upgrade to 1.21.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-34447 attacked?

It is attacked with local access, in a software library.

Am I affected by CVE-2026-34447?

Check whether you run Linuxfoundation Onnx or onnx (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-34447: ONNX symlink traversal in external data loading

Q: Which products and versions are affected?

onnx (PyPI) < 1.21.0, ECOSYSTEM:introduced=0,fixed=1.21.0.

Q: Is there a fix for CVE-2026-34447?

Yes. onnx (PyPI): upgrade to 1.21.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-34447 attacked?

It is attacked with local access, in a software library.

Q: Am I affected by CVE-2026-34447?

Check whether you run Linuxfoundation Onnx or onnx (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-34447 · Severity: medium · CVSS 5.5 · Published 2026-04-01

ONNX is an open-source format for artificial intelligence models. A vulnerability in how it loads external data allows a specially crafted model file to read sensitive files from the user's computer. This could lead to the theft of private information if a user is tricked into opening a malicious AI model.

Technologies: onnx (PyPI). Vendors: Linuxfoundation, PyPI.

Quick answers

Is CVE-2026-34447 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-34447 being exploited in the wild.
How severe is CVE-2026-34447?: Medium severity, with a CVSS score of 5.5, published 1 April 2026.
Which products and versions are affected?: onnx (PyPI) < 1.21.0, ECOSYSTEM:introduced=0,fixed=1.21.0.
Is there a fix for CVE-2026-34447?: Yes. onnx (PyPI): upgrade to 1.21.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-34447 attacked?: It is attacked with local access, in a software library.
Am I affected by CVE-2026-34447?: Check whether you run Linuxfoundation Onnx or onnx (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

onnx (PyPI): upgrade to 1.21.0 or later
```
pip install "onnx>=1.21.0"
```

Technical details

A symlink traversal vulnerability exists in `onnx/onnx/checker.cc` within the `resolve_external_data_location` function. While the function attempts to validate that external data paths are relative and reside within the base directory, it uses `std::filesystem::is_regular_file`, which follows symbolic links. An attacker can provide a model where an external data reference points to a symlink within the model directory that targets a sensitive file elsewhere on the filesystem (e.g., `/etc/passwd`). When `load_external_data_for_model` is called, the library will read the contents of the linked file into the model's tensors. This is fixed in version 1.21.0.

Affected products

ONNX onnx < 1.21.0

Identifiers

CVE-2026-34447
GHSA-p433-9wv8-28xj
PYSEC-2026-104

Timeline

2026-03-31: disclosed
2026-04-01: advisory
2026-04-01: patched: Fixed in version 1.21.0

References

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