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Vulnerability · Published Jun 24, 2026 · Assigned by VulnCheck

CVE-2026-56121Feast < 0.63.0 Unauthenticated RCE via ApplyFeatureView gRPC Deserialization

Critical 9.8

In plain English

A critical-severity unsafe deserialization in feast from feast-dev. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.4% (higher than 73% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)1.4%top 27.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack tooling1Public PoC

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
PyPIfeast0.63.0GHSA-q63x-9pfm-mjx4

Affected products (as reported)

VendorProductVersions
feast-dev feast 0 – before 0.63.0

Weakness: CWE-502 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References