CVE-2026-56121
Description
A flaw was found in Feast. This vulnerability allows unauthenticated or unauthorized attackers to achieve remote code execution. By sending a specially crafted gRPC request to the registry server, attackers can exploit an unsafe deserialization process. This enables them to execute operating system commands as the Feast service account, leading to a complete compromise of the affected system.
Statement
Red Hat OpenShift AI ships Feast versions affected by CVE-2026-56121. This flaw allows remote code execution only against the Feast registry gRPC server (feast serve_registry, port 6570) when that service is running and reachable.
Default OpenShift AI installations are not affected. Installing OpenShift AI deploys the Feast operator but does not create a FeatureStore instance or start a registry server. The default FeatureStore configuration runs the online feature server only (feast serve), which does not expose the vulnerable gRPC endpoint. Workbench and pipeline runtime images include Feast as a client library and do not start a registry server.
Red Hat validated this by attempting exploitation against Feast 0.62.0: remote code execution succeeded only when a registry server was explicitly started; the default online-only configuration and library-only images were not exploitable.
Customers who configure a FeatureStore with an explicit registry server (registry.local.server) should treat this as a critical issue and apply the fix (Feast ≥ 0.63.0) when available. Enabling authorization alone does not remediate affected versions because unsafe deserialization occurs before authorization checks.
Red Hat rates this Important for OpenShift AI overall, reflecting that the vulnerable component is present but the attack surface is not exposed under default configurations.
Mitigation
- Restrict network access to Feature Server / registry endpoints (NetworkPolicy, Route auth, no public exposure).
- Do not expose the Feast registry gRPC port to untrusted networks; place behind OpenShift Route + platform authentication.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | N/A | 8.8 |
| Attack Vector | Adjacent Network | N/A | Adjacent Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Application Data; Unexpected State
Attackers can modify unexpected objects or data that was assumed to be safe from modification. Deserialized data or code could be modified without using the provided accessor functions, or unexpected functions could be invoked.
Availability
Technical Impact: DoS: Resource Consumption (CPU)
If a function is making an assumption on when to terminate, based on a sentry in a string, it could easily never terminate.
Other
Technical Impact: Varies by Context
The consequences can vary widely, because it depends on which objects or methods are being deserialized, and how they are used. Making an assumption that the code in the deserialized object is valid is dangerous and can enable exploitation. One example is attackers using gadget chains to perform unauthorized actions, such as generating a shell.
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