Summary
etcd: Authorization bypasses in multiple APIs
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
Community efforts help keep etcd secure
The etcd community thanks Isaac David, bugbunny.ai, Asim Viladi Oglu Manizada, Alex Schapiro & Ahmed Allam from Strix security, Luke Francis, and @OLU-DEVX for reporting these vulnerabilities.
Dependency Between Reported Issues
These issues all originate from the same underlying flaw in the gRPC API layer.
They affect the same API surface and share a common root cause. In practice, the fix is implemented as a single, unified change at the API layer, which resolves all issues together.
Given this, we believe these issues are best treated as a single vulnerability and should be assigned a single CVE.
Impact
What kind of vulnerability is it? Who is impacted?
Multiple vulnerabilities allow unauthorized users to bypass authentication or authorization checks and call certain etcd functions in clusters that expose the gRPC API to untrusted or partially trusted clients.
In unpatched etcd clusters with etcd auth enabled, unauthorized users are able to:
- call MemberList and learn cluster topology, including member IDs and advertised endpoints
- call Alarm, which can be abused for operational disruption or denial of service
- use Lease APIs, interfering with TTL-based keys and lease ownership
- trigger compaction, permanently removing historical revisions and disrupting watch, audit, and recovery workflows
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 perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Has the problem been patched? What versions should users upgrade to?
These vulnerabilities are patched in the following versions:
- etcd 3.6.9
- etcd 3.5.28
- etcd 3.4.42
Frequently Asked Questions
- What is CVE-2026-33413? CVE-2026-33413 is a high-severity missing 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 perform an authorization check before performing a sensitive operation.
- Which packages are affected by CVE-2026-33413?
go.etcd.io/etcd/v3(go) (versions >= 3.6.0-alpha.0, <= 3.6.8)go.etcd.io/etcd(go) (versions <= 3.3.27)
- Is there a fix for CVE-2026-33413? Yes. CVE-2026-33413 is fixed in 3.6.9, 3.5.28, 3.4.42. Upgrade to this version or later.
- Is CVE-2026-33413 exploitable, and should I be worried? Whether CVE-2026-33413 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
- What actually determines whether CVE-2026-33413 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.
- How do I fix CVE-2026-33413?
- Upgrade
go.etcd.io/etcd/v3to 3.6.9 or later - Upgrade
go.etcd.io/etcd/v3to 3.5.28 or later - Upgrade
go.etcd.io/etcd/v3to 3.4.42 or later
- Upgrade