CVE-2026-34447 ONNX: External Data Symlink Traversal
Attackers can read arbitrary files outside the model directory via symlink traversal in ONNX external data loading.
- 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
What is CVE-2026-34447?
CVE-2026-34447 is a medium-severity path traversal vulnerability in onnx, published on 1 Apr 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. Prior to version 1.21.0, there is a symlink traversal vulnerability in external data loading allows reading files outside the model directory. This issue has been patched in version 1.21.0.
Which versions are affected by CVE-2026-34447?
3 open source packages ship an affected version, including onnx. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
onnx PyPI | All versions | 1.21.0 |
onnx PyPI | All versions | 1.21.0 |
onnx PyPI | All versions | 1.21.0 |
Products include Linuxfoundation Onnx.
How do I fix CVE-2026-34447?
Upgrade onnx to 1.21.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-34447 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34447 exists.
Other vulnerabilities in onnx
- CVE-2025-51480 Path traversal in n/a
- CVE-2024-5187 Arbitrary File Overwrite in download_model_with_test_data in onnx/onnx
- CVE-2026-27489 ONNX: Path Traversal via Symlink
- CVE-2026-34445 ONNX: Malicious ONNX models can crash servers by exploiting unprotected object settings.
- CVE-2026-28500 ONNX Untrusted Model Repository Warnings Suppressed by silent=True in onnx.hub.load() — Silent Supply-Chain Attack
Sources
Also known as DEBIAN-CVE-2026-34447, ECHO-9d3d-c34f-5dfc, GHSA-p433-9wv8-28xj, PYSEC-2026-104, UBUNTU-CVE-2026-34447.