CVE-2026-4035: lfprojects mlflow

Vulnerability summary

CVE-2026-4035 is a critical (CVSS 9.1) vulnerability in lfprojects mlflow. EPSS estimates a 0.66% chance of exploitation in the next 30 days, higher than 50.6% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 03-06-2026
   PublishedVulnerability first disclosed.
2. 14-08-2026
   Last modifiedVulnerability information updated.

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.

• CWE-201Insertion of Sensitive Information Into Sent DataThe code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.