etcd: Nested etcd transactions bypass RBAC authorization checks

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

• CVE-2026-33343: 0.22% estimated exploitation activity in the next 30 days; percentile 12.44 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact What kind of vulnerability is it? Who is impacted? 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. Patches Has the problem been patched? What versions should users upgrade to? This vulnerability is patched in the following versions: etcd 3.6.9 etcd 3.5.28 etcd 3.4.42 Workarounds Is there a way for users to fix or remediate the vulnerability without upgrading? 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…

Published by the source

20 Mar 2026, 20:34 UTC

Last modified by the source

27 Mar 2026, 20:48 UTC

Source last checked

26 Oct 2026, 15:18 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-rfx7-8w68-q57q

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# Patch Next advisory brief: CVE-2026-33343

Advisory: etcd: Nested etcd transactions bypass RBAC authorization checks
IDs: CVE-2026-33343, GHSA-rfx7-8w68-q57q
Record: https://patchnext.com/advisories/cve-2026-33343 (revision 1, source checked 26 Oct 2026, 15:18 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: go.etcd.io/etcd/v3 3.6.9, 3.5.28, 3.4.42. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go go.etcd.io/etcd/v3: affected >= 3.6.0-alpha.0, <= 3.6.8; >= 3.5.0-alpha.0, <= 3.5.27; <= 3.4.41; fixed in 3.6.9, 3.4.42, 3.5.28
- Go go.etcd.io/etcd: affected <= 3.3.27

## Suggested inspection (read-only)
- Go go.etcd.io/etcd/v3: check the installed version with your package manager.
- Go go.etcd.io/etcd: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on go.etcd.io/etcd/v3, go.etcd.io/etcd.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-rfx7-8w68-q57q (GitHub-reviewed advisory GHSA-rfx7-8w68-q57q lists affected ranges: Go go.etcd.io/etcd/v3 >=3.6.0-alpha.0 =3.5.0-alpha.0 =0 =0 <=3.3.27)

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