What is CVE-2026-56121?

CVE-2026-56121 is a critical-severity vulnerability in Feast-dev Feast, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-06-24.

How severe is CVE-2026-56121?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Deserialization in Feast-dev Feast

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…

Vulnerability class: Insecure Deserialization

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Feast-dev Feast — versions 0

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

disclosure@vulncheck.com (technical-description, exploit)
disclosure@vulncheck.com (release-notes)
disclosure@vulncheck.com (patch)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-56121?: CVE-2026-56121 is a critical-severity vulnerability in Feast-dev Feast, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-06-24.
How severe is CVE-2026-56121?: Critical severity. CVSS v3 base score is 9.8 out of 10.