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Description

A vulnerability in mlflow/mlflow versions prior to 3.11.0 allows for the resolution of environment variables in AI Gateway secrets, which can be exploited to exfiltrate sensitive server-side environment credentials to an attacker-controlled endpoint. This issue arises because the `api_key` field in gateway secrets can accept `$ENV_VAR` references, which are resolved against the MLflow server's environment during runtime. The resolved secrets are then sent in provider authentication headers to the configured upstream `api_base`. This vulnerability can be exploited by low-privileged authenticated users in basic-auth deployments or by unauthenticated users in default deployments without `basic-auth`. The impact includes potential leakage of sensitive credentials such as cloud artifact credentials (`AWS_ACCESS_KEY_ID`, `AWS_SECRET_ACCESS_KEY`), which could lead to artifact poisoning and cross-boundary code execution in downstream environments. The issue is fixed in version 3.11.0.

PUBLISHED Reserved 2026-03-12 | Published 2026-06-03 | Updated 2026-06-03 | Assigner @huntr_ai




CRITICAL: 9.1CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L

Problem types

CWE-201 Insertion of Sensitive Information Into Sent Data

Product status

Any version before 3.11.0
affected

References

huntr.com/bounties/f8e591a0-0f19-4910-b82e-16c9956f2233 exploit

huntr.com/bounties/f8e591a0-0f19-4910-b82e-16c9956f2233

github.com/...ommit/4a3f2f720cb4f058c9e0c5b883e0acc9ab64a7f3

cve.org (CVE-2026-4035)

nvd.nist.gov (CVE-2026-4035)

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