CVE-2026-28500

What's the issue

Passing silent=True to onnx.hub.load() kills all trust warnings and user prompts. This means a model can be downloaded from any unverified GitHub repo with zero user awareness.

if not _verify_repo_ref(repo) and not silent:
    # completely skipped when silent=True
    print("The model repo... is not trusted")
    if input().lower() != "y":
        return None

On top of that, the SHA256 integrity check is useless here, it validates against a manifest that lives in the same repo the attacker controls, so the hash will always match.

Resolved by removing the feature

References

• Write-up

Any pipeline using hub.load() with silent=True and an external repo string is silently loading whatever the repo owner ships. If that model executes arbitrary code on load, the attacker has access to the machine.

CVE-2026-28500 has a CVSS score of 8.6 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.21.0rc1); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-28500? CVE-2026-28500 is a high-severity security vulnerability in onnx (pip), affecting versions <= 1.20.1. It is fixed in 1.21.0rc1.
2. How severe is CVE-2026-28500? CVE-2026-28500 has a CVSS score of 8.6 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of onnx are affected by CVE-2026-28500? onnx (pip) versions <= 1.20.1 is affected.
4. Is there a fix for CVE-2026-28500? Yes. CVE-2026-28500 is fixed in 1.21.0rc1. Upgrade to this version or later.
5. Is CVE-2026-28500 exploitable, and should I be worried? Whether CVE-2026-28500 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-28500 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-28500? Upgrade onnx to 1.21.0rc1 or later.