CVE-2026-56121
Feast < 0.63.0 Unauthenticated RCE via ApplyFeatureView gRPC Deserialization
- Published
- Jun 24, 2026
- Updated
- Aug 28, 2026
- Assigning CNA
- VulnCheck
- Evidence observed
- Aug 8, 2026
Primary CVSS
nvd · CVSS 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XLow · next 30 days
- Percentile
- 71.0%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
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_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.
Sources
3- CVE-2026-56121_exploitExploit
Unauthenticated RCE exploit for Feast registry gRPC server (CVE-2026-56121) using dill deserialization. Includes payload generation, reverse shell support, and target identification via gRPC reflection.
CVE-2026-56121 — Feast <0.63.0 unauthenticated RCE via gRPC registry dill.loads of OnDemandFeatureView UDF (pre-auth). Lab + PoC, verified e2e.
Responsible use
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