Unauthenticated RCE and Data Access in Feast via Default Configuration

A security vulnerability (CVE-2026-18941) exists within the Feast feature store platform, specifically affecting both the Feast SDK and the feast-operator. The core of the issue lies in a default configuration setting labeled as "no_auth." Under this configuration, the platform fails to initialize a security manager, effectively leaving the feature-server, registry-server, and offline-server endpoints entirely unprotected.

This misconfiguration enables unauthenticated and unauthorized remote attackers to interact directly with these sensitive API endpoints. The scope of impact is significant; beyond simple unauthorized data access, an attacker can store and execute arbitrary malicious User-Defined Functions (UDFs) on the feature-server, leading to remote code execution (RCE). Furthermore, attackers can disrupt availability by triggering the re-materialization of all tenant features, resulting in a Denial of Service (DoS) condition. This issue is particularly critical for multi-tenant environments where the lack of authentication allows for broad cross-tenant data exposure. Defenders should audit all Feast deployments for the presence of the "no_auth" configuration and implement robust authentication mechanisms immediately.

Impact

Successful exploitation of this vulnerability allows unauthenticated attackers to gain complete control over feature store operations, leading to critical data exfiltration, remote code execution within the infrastructure, and significant service degradation through denial of service attacks. The vulnerability affects any organization utilizing Feast or feast-operator with default security settings, particularly in cloud-native multi-tenant environments where data isolation is a primary security requirement.

Recommendation

• Audit existing Feast and feast-operator deployments to identify instances where the "no_auth" configuration is active in production environments.
• Update Feast SDK and feast-operator components to versions that enforce secure authentication defaults.
• Restrict network access to feature-server, registry-server, and offline-server endpoints using firewalls or Service Mesh policies (mTLS/RBAC) to ensure only authorized traffic reaches these services.
• Monitor webserver access logs for anomalous POST requests directed at UDF registration or feature-server management endpoints from unauthorized IP ranges.