CVE-2026-4035

critical

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.

References

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

https://github.com/mlflow/mlflow/commit/4a3f2f720cb4f058c9e0c5b883e0acc9ab64a7f3

Details

Source: Mitre, NVD

Published: 2026-06-03

Updated: 2026-06-03

Risk Information

CVSS v2

Base Score: 8

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.1

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

Severity: Critical

EPSS

EPSS: 0.00278