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ONNX Untrusted Model Repository Warnings Suppressed by silent=True in onnx.hub.load() — Silent Supply-Chain Attack

High severity GitHub Reviewed Published Mar 16, 2026 in onnx/onnx • Updated Mar 19, 2026

Package

pip onnx (pip)

Affected versions

<= 1.20.1

Patched versions

None

Description

Summary

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.

The Technical Flaw

The vulnerability is located in onnx/hub.py. The security gate uses a short-circuit evaluation that prioritizes the "silent" preference over the trust requirement:

if not _verify_repo_ref(repo) and not silent:
    # This block (Warning + User Input) is SKIPPED if silent=True
    print("The model repo... is not trusted")
    if input().lower() != "y":
        return None

Key Points of Failure:
Complete Suppression: If a developer or a third-party library sets silent=True, the application will download and execute models from any attacker-controlled GitHub repository without notifying the user.
Integrity Verification Bypass: The SHA256 integrity check validates the model against a manifest file. Since the attacker controls the repository, they also control the manifest, allowing them to provide a "valid" hash for a malicious model.

Impact

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.

References

@javier-intel javier-intel published to onnx/onnx Mar 16, 2026
Published to the GitHub Advisory Database Mar 16, 2026
Reviewed Mar 16, 2026
Published by the National Vulnerability Database Mar 18, 2026
Last updated Mar 19, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(1st percentile)

Weaknesses

Insufficient Verification of Data Authenticity

The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. Learn more on MITRE.

Download of Code Without Integrity Check

The product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code. Learn more on MITRE.

Protection Mechanism Failure

The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product. Learn more on MITRE.

CVE ID

CVE-2026-28500

GHSA ID

GHSA-hqmj-h5c6-369m

Source code

Credits

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