etcd is a distributed key-value store for the data of a distributed system. Prior to versions 3.4.42, 3.5.28, and 3.6.9, an authenticated user with RBAC restricted permissions on key ranges can use nested transactions to bypass all key-level authorization. This allows any authenticated user with direct access to etcd to effectively ignore all key range restrictions, accessing the entire etcd data store. Kubernetes does not rely on etcd’s built-in authentication and authorization. Instead, the API server handles authentication and authorization itself, so typical Kubernetes deployments are not affected. Versions 3.4.42, 3.5.28, and 3.6.9 contain a patch. If upgrading is not immediately possible, reduce exposure by treating the affected RPCs as unauthenticated in practice. Restrict network access to etcd server ports so only trusted components can connect and require strong client identity at the transport layer, such as mTLS with tightly scoped client certificate distribution.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-rfx7-8w68-q57q etcd: Nested etcd transactions bypass RBAC authorization checks
Fixes

Solution

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Workaround

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History

Thu, 26 Mar 2026 13:45:00 +0000

Type Values Removed Values Added
Description etcd is a distributed key-value store for the data of a distributed system. Prior to versions 3.4.42, 3.5.28, and 3.6.9, an authenticated user with RBAC restricted permissions on key ranges can use nested transactions to bypass all key-level authorization. This allows any authenticated user with direct access to etcd to effectively ignore all key range restrictions, accessing the entire etcd data store. Kubernetes does not rely on etcd’s built-in authentication and authorization. Instead, the API server handles authentication and authorization itself, so typical Kubernetes deployments are not affected. Versions 3.4.42, 3.5.28, and 3.6.9 contain a patch. If upgrading is not immediately possible, reduce exposure by treating the affected RPCs as unauthenticated in practice. Restrict network access to etcd server ports so only trusted components can connect and require strong client identity at the transport layer, such as mTLS with tightly scoped client certificate distribution.
Title etcd: Nested etcd transactions bypass RBAC authorization checks
Weaknesses CWE-863
References
Metrics cvssV3_1

{'score': 0, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-26T13:23:48.247Z

Reserved: 2026-03-18T22:15:11.813Z

Link: CVE-2026-33343

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-03-26T14:16:13.137

Modified: 2026-03-26T15:13:15.790

Link: CVE-2026-33343

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses