CVE-2026-56121

Critical

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.

SeverityCritical

CVSS9.8

Exploit probability—

ProductFeast

PublishedJun 24, 2026

First seenJun 24, 2026

Weakness typeCWE-502Deserialization of untrusted data

How to fix

Update

feast0.63.0 or later

Patches

github.com/feast-dev/feast/commit/835cda8e2c1359f1f496ad72701dbd6a73bdb25a

Vendor advisories

Affected products

Product	Affected versions	Fixed in
feastPyPI	v < 0.63.0	0.63.0

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