---
id: CVE-2026-56121
title: >-
  Feast before 0.63.0 contains an unsafe deserialization vulnerability that
  allows unauthenticated or unauthorized attackers to achieve remote code
  execution by sending a crafted gRPC request to the registry server
summary: >-
  Feast before 0.63.0 contains an unsafe deserialization vulnerability that
  allows unauthenticated or unauthorized attackers to achieve remote code
  execution by sending a crafted gRPC request to the registry server. The
  user_defined_functi…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-502
published: '2026-06-24'
updated: '2026-08-28'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56121'
references:
  - url: >-
      https://github.com/feast-dev/feast/commit/835cda8e2c1359f1f496ad72701dbd6a73bdb25a
    label: disclosure@vulncheck.com
  - url: 'https://github.com/feast-dev/feast/releases/tag/v0.63.0'
    label: disclosure@vulncheck.com
  - url: 'https://huntr.com/bounties/d64b8111-180b-46ba-afa3-c877fda2ede6'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/feast-unauthenticated-rce-via-applyfeatureview-grpc-deserialization
    label: disclosure@vulncheck.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:60520'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-56121'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2492229'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56121.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-56121'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56121'
  - url: 'https://access.redhat.com/errata/RHSA-2026:84734'
  - url: 'https://github.com/advisories/GHSA-q63x-9pfm-mjx4'
tags:
  - nvd
  - exploit-available
  - csaf
  - vex
  - red-hat
  - ghsa
  - pip
epss: 0.01406
epssPercentile: 0.7246
ingestedAt: '2026-08-29T00:27:53.736Z'
exploits:
  github: 3
  githubRepos:
    - 'https://github.com/0xdak/CVE-2026-56121_exploit'
    - 'https://github.com/BiiTts/CVE-2026-56121-Feast-Unauth-RCE'
    - 'https://github.com/joaovicdev/EXPLOIT-CVE-2026-56121'
  checkedAt: '2026-10-27T19:04:30.334Z'
exploitAvailable: true
vendor: Red Hat
product: Red Hat OpenShift AI 3.4
affected:
  - openshift_ai_rhoai
  - openshift_ai 3.4
patched:
  - openshift_ai 3.4
scores:
  nvd: 9.8
  vendor: 8.8
  ghsa: 9.8
aliases:
  - GHSA-q63x-9pfm-mjx4
ecosystem: pip
---

## Overview

Feast before 0.63.0 contains an unsafe deserialization vulnerability that allows unauthenticated or unauthorized attackers to achieve remote code execution by sending a crafted gRPC request to the registry server. The user_defined_function.body field of an OnDemandFeatureView spec is decoded from base64 and passed to dill.loads() before any authorization check is performed, enabling attackers to embed a malicious serialized Python object with an arbitrary __reduce__ method to execute OS commands as the feast service account.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:84734** · Red Hat · fixed in: Red Hat OpenShift AI 3.4 · released 2026-10-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:84734)
- **RHSA-2026:60520** · Red Hat · fixed in: Red Hat OpenShift AI 3.4 · released 2026-08-27 · [advisory](https://access.redhat.com/errata/RHSA-2026:60520)
- **Red Hat VEX** · Important · affected: Red Hat OpenShift AI (RHOAI) · no fix planned: Red Hat OpenShift AI (RHOAI) · updated 2026-10-19 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56121.json)

## Package advisory (CVE-2026-56121)

Affected packages:

- `feast < 0.63.0`

Patched in:

- `feast 0.63.0`

Source: https://github.com/advisories/GHSA-q63x-9pfm-mjx4