CVE-2026-28500 ONNX Untrusted Model Repository Warnings Suppressed by silent=True in onnx.hub.load() — Silent Supply-Chain Attack
Attackers can silently load malicious models via onnx.hub.load() with silent=True, bypassing security warnings to exfiltrate data or execute code.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-28500?
CVE-2026-28500 is a high-severity vulnerability in onnx, published on 18 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Open Neural Network Exchange (ONNX) is an open standard for machine learning interoperability. In versions up to and including 1.20.1, a security control bypass exists in onnx.hub.load() due to improper logic in the repository trust verification mechanism. While the function is designed to warn users when loading models from non-official sources, the use of the silent=True parameter completely suppresses all security warnings and confirmation prompts. This vulnerability transforms a standard model-loading function into a vector for Zero-Interaction Supply-Chain Attacks. When chained with file-system vulnerabilities, an attacker can silently exfiltrate sensitive files (SSH keys, cloud credentials) from the victim's machine the moment the model is loaded. As of time of publication, no known patched versions are available.
Which versions are affected by CVE-2026-28500?
3 open source packages ship an affected version, including onnx. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
onnx PyPI | All versions | 1.21.0rc1 |
onnx PyPI | All versions | 1.21.0rc1 |
onnx PyPI | All versions | 1.21.0rc1 |
Products include Linuxfoundation Onnx.
How do I fix CVE-2026-28500?
Upgrade onnx to 1.21.0rc1 or later.
Is CVE-2026-28500 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-28500 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-2022-25882 Directory Traversal in onnx
Sources
Also known as DEBIAN-CVE-2026-28500, ECHO-a2aa-110f-94f8, GHSA-hqmj-h5c6-369m, PYSEC-2026-103, UBUNTU-CVE-2026-28500.