CVE-2026-56121

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.

CVSS 4.0

9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

1.4% chance of exploitation in the next 30 days; higher than 72% of CVEs (scores of 2026-10-25)

CWE

CWE-502

Published

2026-06-24

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

References

• https://github.com/feast-dev/feast/commit/835cda8e2c1359f1f496ad72701dbd6a73bdb25a
• https://github.com/feast-dev/feast/releases/tag/v0.63.0
• https://huntr.com/bounties/d64b8111-180b-46ba-afa3-c877fda2ede6
• https://www.vulncheck.com/advisories/feast-unauthenticated-rce-via-applyfeatureview-grpc-deserialization
• https://access.redhat.com/errata/RHSA-2026:60520

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