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, unauthorized users may 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; and/or 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. 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/or require strong client identity at the transport layer, such as mTLS with tightly scoped client certificate distribution.
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, unauthorized users may 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; and/or 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. 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/or require strong client identity at the transport layer, such as mTLS with tightly scoped client certificate distribution.
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, unauthorized users may 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; and/or 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. 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/or require strong client identity at the transport layer, such as mTLS with tightly scoped client certificate distribution.
### 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.
### Patches
_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
### 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.
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: Mar 26, 2026, 1:36:10 PM
dateUpdated: Mar 26, 2026, 6:51:42 PM
8 related source bulletins · separate from aliases
openSUSE-SU-2026:10562-1: flannel-0.28.4-1.1 on GA media
CVE-2026-33413
RHSA-2026:23345: Red Hat Security Advisory: Multicluster Global Hub 1.6.2 security update
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
Source analysis status: Analyzed
Weakness classifications: CWE-862
Original publisher date fields
published: 2026-03-26T14:16:13.490
lastModified: 2026-06-17T10:37:27.137
1 source CPE criteria · context only
cpe:2.3:a:etcd:etcd:*:*:*:*:*:*:*:*
The original JSON retains the logical configuration operators, exclusions and version bounds.
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.