etcd versions 3.2.x before 3.2.26 and 3.3.x before 3.3.11 are vulnerable to an improper authentication issue when role-based access control (RBAC) is used and client-cert-auth is enabled. If an etcd client server TLS certificate contains a Common Name (CN) which matches a valid RBAC username, a remote attacker may authenticate as that user with any valid (trusted) client certificate in a REST API request to the gRPC-gateway.
{ "binaries": [ { "binary_version": "3.2.17+dfsg-1ubuntu0.1+esm2", "binary_name": "etcd" }, { "binary_version": "3.2.17+dfsg-1ubuntu0.1+esm2", "binary_name": "etcd-client" }, { "binary_version": "3.2.17+dfsg-1ubuntu0.1+esm2", "binary_name": "etcd-server" }, { "binary_version": "3.2.17+dfsg-1ubuntu0.1+esm2", "binary_name": "golang-etcd-server-dev" } ] }