Feast < 0.63.0 Unauthenticated RCE via ApplyFeatureView gRPC Deserialization
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-56121
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 14:53 UTC · Revision 1
Source evidence
Feast < 0.63.0 Unauthenticated RCE via ApplyFeatureView gRPC Deserialization
core-osv · Original sourcePublished 24 Jun 2026, 14:49 UTC
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.
osv:CVE-2026-56121
Complete source record
{
"id": "f0dbea0f99b5f347c593148e22ed1d82b792da9a2d33dc82430b7001b755e270",
"url": "https://osv.dev/vulnerability/CVE-2026-56121",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Feast < 0.63.0 Unauthenticated RCE via ApplyFeatureView gRPC Deserialization",
"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.",
"evidence": "osv:CVE-2026-56121",
"products": [],
"severity": "critical",
"structured": {
"id": "CVE-2026-56121",
"aliases": [
"CVE-2026-56121"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "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"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/feast-dev/feast",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "50ad181b420a8c95cdd421d3908d298fd355b1b5"
},
{
"fixed": "835cda8e2c1359f1f496ad72701dbd6a73bdb25a"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "0.63.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"fixed": "50ad181b420a8c95cdd421d3908d298fd355b1b5"
}
],
"source": "REFERENCES_TAG",
"original_tag": "v0.63.0"
},
{
"range": [
{
"fixed": "835cda8e2c1359f1f496ad72701dbd6a73bdb25a"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"v0.62.0",
"v0.60.0",
"v0.59.0",
"v0.58.0",
"v0.54.0",
"v0.57.0",
"v0.56.0",
"v0.55.0",
"v0.53.0",
"v0.52.0",
"v0.51.0",
"v0.50.0",
"v0.49.0",
"v0.48.0",
"v0.47.0",
"v0.46.0",
"v0.45.0",
"v0.44.0",
"v0.43.0",
"v0.42.0",
"v0.41.0",
"v0.40.0",
"v0.39.0",
"v0.38.0",
"v0.37.0",
"v0.36.0",
"v0.35.0",
"v0.34.0",
"v0.33.0",
"v0.32.0",
"v0.31.0",
"v0.30.0",
"v0.29.0",
"v0.28.0",
"v0.27.0",
"v0.26.0",
"v0.25.0",
"v0.24.0",
"v0.23.0",
"v0.22.0",
"v0.21.0",
"v0.20.0",
"v0.19.0",
"v0.18.0",
"v0.17.0",
"v0.16.0",
"v0.14.0",
"v0.13.0",
"v0.12.0",
"v0.11.0",
"v0.10.0",
"v0.9.0-rc.2",
"v0.9.0-rc.1",
"v0.8.0",
"sdk/go/v0.8.0",
"v0.8.0-rc.3",
"v0.8.0-rc.2",
"v0.8.0-rc.1",
"v0.6.0",
"v0.5.0",
"v0.4.2",
"v0.4.1",
"v0.4.0",
"v0.3.2",
"v0.3.0",
"v0.1.1",
"v0.1.0",
"v0.0.1"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-56121.json"
}
}
],
"modified": "2026-10-28T02:30:29.566055422Z",
"provider": "osv",
"references": [
"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56121.json",
"https://access.redhat.com/errata/RHSA-2026:60520",
"https://access.redhat.com/security/cve/CVE-2026-56121",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56121.json",
"https://github.com/feast-dev/feast/releases/tag/v0.63.0",
"https://nvd.nist.gov/vuln/detail/CVE-2026-56121",
"https://www.vulncheck.com/advisories/feast-unauthenticated-rce-via-applyfeatureview-grpc-deserialization",
"https://bugzilla.redhat.com/show_bug.cgi?id=2492229",
"https://github.com/feast-dev/feast/commit/835cda8e2c1359f1f496ad72701dbd6a73bdb25a",
"https://github.com/feast-dev/feast",
"https://huntr.com/bounties/d64b8111-180b-46ba-afa3-c877fda2ede6"
],
"provider_metadata": {
"cwe_ids": [
"CWE-502"
],
"cna_assigner": "VulnCheck",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56121.json"
}
},
"related_cves": [
{
"value": "CVE-2026-56121",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 496440,
"published_at": "2026-06-24T14:49:11.49+00:00"
}