The vulnerability CVE-2026-18941 affects Feast and feast-operator components used in Red Hat OpenShift AI (RHOAI). By default, both the Feast SDK and feast-operator use a 'no_auth' configuration, meaning no security manager is installed. This default setting exposes feature-server, registry-server, and offline-server endpoints to unauthenticated and unauthorized access within the cluster network. A remote attacker exploiting this missing authentication can store malicious User-Defined Functions (UDFs) on the feature-server to achieve remote code execution (RCE), trigger denial of service (DoS) by forcing re-materialization of tenant features, and gain unauthorized access to data across tenants in shared multi-tenant deployments. The vulnerability is due to missing authentication controls (CWE-306).

The vulnerability allows an attacker with network access to the cluster to perform unauthenticated actions on critical Feast services. This can lead to remote code execution by uploading malicious UDFs, denial of service by forcing expensive re-materialization of features, and unauthorized access to sensitive data across tenants. The impact includes confidentiality breaches and potential privilege escalation within the affected environment. The CVSS v3.1 score is 7.7 (high severity) with network attack vector, low attack complexity, low privileges required, no user interaction, and scope changed. Confidentiality impact is high, with no integrity or availability impact reported.

Red Hat advises configuring Feast deployments to use Kubernetes RBAC authentication instead of the default 'no_auth' setting. FeatureStore Custom Resources (CRs) should explicitly specify an authentication mechanism other than 'no_auth'. For Feast SDK usage, avoid using 'no_auth' in production unless explicitly acknowledged with the environment variable 'FEAST_INSECURE_NO_AUTH=1'. These configuration changes require redeployment or restart of the affected Feast services. No official patch or fix version is currently confirmed; users should follow the vendor advisory for updates and apply recommended configuration changes promptly.