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.
etcd is a distributed key-value store for the data of a distributed system. Prior to 3.5.32 and 3.6.13, when etcd is configured with --listen-client-http-urls to split HTTP and gRPC client endpoints onto separate listeners, the --client-crl-file Certificate Revocation List is not enforced on the gRPC listener, allowing a client with a revoked certificate to authenticate successfully over gRPC. This issue is fixed in versions 3.5.32 and 3.6.13.
Impact What kind of vulnerability is it? Who is impacted?
A vulnerability in etcd allows read access via PrevKv, or lease attachment in Put requests within transaction operations, to bypass RBAC authorization checks. An authenticated user without sufficient read or lease-related permissions may be able to access unauthorized data or attach leases by invoking transaction operations with these features enabled.
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 3.6.11 - etcd 3.5.30 - etcd 3.4.44
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
Samy Ghannad (@SamyGhannad on Github) reported that read access via PrevKv in a Put request within etcd transactions bypassed RBAC authorization checks. Benjamin Wang (@ahrtr ) further analyzed that lease attachment in a Put request within etcd transactions also bypassed RBAC authorization checks
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 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.