In MLflow version 3.9.0, the MLflow Assistant feature introduced improper origin validation in its /ajax-api endpoints. This vulnerability allows a remote attacker to exploit cross-origin requests from a malicious webpage to interact with the MLflow Assistant running on a victim's local machine. By bypassing the loopback-only restriction, the attacker can modify the Assistant's configuration to enable full access, which in turn allows the execution of arbitrary commands via the Claude Code sub-agent. This issue is resolved in version 3.10.0.

MLflow 3.9.0 with basic-auth (--app-name basic-auth) fails to enforce authorization checks for multiple Gateway API 'list' endpoints. Specifically, the BEFOREREQUESTHANDLERS dictionary in mlflow/server/auth/init.py does not include entries for ListGatewaySecretInfos, ListGatewayEndpoints, and ListGatewayModelDefinitions. This allows any authenticated user, regardless of their assigned permissions, to enumerate all gateway secrets, endpoints, and model definitions. This vulnerability exposes sensitive information, such as API keys, endpoint configurations, and proprietary model definitions, to unauthorized users.