CVE-2026-33343

etcd: Nested etcd transactions bypass RBAC authorization checks

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 components can connect
• require strong client identity at the transport layer, such as mTLS with tightly scoped client certificate
  distribution

Reporters

Our community helps keep etcd secure

SIG-Etcd thanks community members Luke Francis and Battulga Byambaa for reporting this vulnerability.

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.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

Kodem intelligence

Already deployed Kodem?

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

1. What is CVE-2026-33343? CVE-2026-33343 is a low-severity incorrect authorization vulnerability in go.etcd.io/etcd/v3 (go), affecting versions >= 3.6.0-alpha.0, <= 3.6.8. It is fixed in 3.6.9, 3.5.28, 3.4.42. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. Which packages are affected by CVE-2026-33343?
   • go.etcd.io/etcd/v3 (go) (versions >= 3.6.0-alpha.0, <= 3.6.8)
   • go.etcd.io/etcd (go) (versions <= 3.3.27)
3. Is there a fix for CVE-2026-33343? Yes. CVE-2026-33343 is fixed in 3.6.9, 3.5.28, 3.4.42. Upgrade to this version or later.
4. Is CVE-2026-33343 exploitable, and should I be worried? Whether CVE-2026-33343 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2026-33343 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2026-33343?
   • Upgrade go.etcd.io/etcd/v3 to 3.6.9 or later
   • Upgrade go.etcd.io/etcd/v3 to 3.5.28 or later
   • Upgrade go.etcd.io/etcd/v3 to 3.4.42 or later

Other vulnerabilities in go.etcd.io/etcd/v3