Is CVE-2026-4035 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-4035 being exploited in the wild.

How severe is CVE-2026-4035?

Critical severity, with a CVSS score of 9.1, published 3 June 2026.

Which products and versions are affected?

mlflow (PyPI) < 3.11.0, ECOSYSTEM:introduced=0,fixed=3.11.0.

Is there a fix for CVE-2026-4035?

Yes. mlflow (PyPI): upgrade to 3.11.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-4035 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-4035?

Check whether you run mlflow (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-2026-4035: MLflow AI Gateway credential exfiltration via environment variable resolution

Q: Which products and versions are affected?

mlflow (PyPI) < 3.11.0, ECOSYSTEM:introduced=0,fixed=3.11.0.

Q: Is there a fix for CVE-2026-4035?

Yes. mlflow (PyPI): upgrade to 3.11.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-4035 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-4035?

Check whether you run mlflow (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-2026-4035 · Severity: critical · CVSS 9.1 · Published 2026-06-03

MLflow is an open-source platform used by teams to manage machine learning workflows and AI models. A security flaw in its AI Gateway component allows attackers to trick the system into revealing sensitive server-side credentials, such as AWS access keys. If exploited, this could allow an attacker to steal cloud credentials, potentially leading to unauthorized data access or the ability to tamper with machine learning models.

Technologies: mlflow (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-4035 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-4035 being exploited in the wild.
How severe is CVE-2026-4035?: Critical severity, with a CVSS score of 9.1, published 3 June 2026.
Which products and versions are affected?: mlflow (PyPI) < 3.11.0, ECOSYSTEM:introduced=0,fixed=3.11.0.
Is there a fix for CVE-2026-4035?: Yes. mlflow (PyPI): upgrade to 3.11.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-4035 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-4035?: Check whether you run mlflow (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

mlflow (PyPI): upgrade to 3.11.0 or later
```
pip install "mlflow>=3.11.0"
```

Technical details

A vulnerability in MLflow's AI Gateway component (prior to version 3.11.0) stems from the improper handling of the `api_key` field in gateway secrets. The system resolves `$ENV_VAR` references within this field against the server's environment variables at runtime. An attacker can configure a gateway secret to reference sensitive variables (e.g., `AWS_SECRET_ACCESS_KEY`) and set the `api_base` to an external endpoint they control. When the gateway attempts to authenticate to the upstream provider, it sends the resolved secret in the authentication header to the attacker's server. This can be exploited by low-privileged users in basic-auth environments or unauthenticated users in default deployments. The fix in version 3.11.0 gates this resolution behavior behind a new configuration flag.

Affected products

MLflow MLflow < 3.11.0
Red Hat Red Hat OpenShift AI (RHOAI)

Identifiers

CVE-2026-4035
GHSA-g35p-px32-whv6
PYSEC-2026-2222

Timeline

2026-06-03: disclosed
2026-06-03: advisory
2026-07-10: patched: GitHub Advisory updated with patch details

References

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