diff --git a/bill-of-materials.json b/bill-of-materials.json
index 9638e8e54..bf9574041 100644
--- a/bill-of-materials.json
+++ b/bill-of-materials.json
@@ -656,6 +656,15 @@
 			}
 		]
 	},
+	{
+		"project": "golang.org/x/sync/errgroup",
+		"licenses": [
+			{
+				"type": "BSD 3-clause \"New\" or \"Revised\" License",
+				"confidence": 0.9663865546218487
+			}
+		]
+	},
 	{
 		"project": "golang.org/x/sys/unix",
 		"licenses": [
diff --git a/tests/e2e/cmux_test.go b/tests/e2e/cmux_test.go
new file mode 100644
index 000000000..51512d57e
--- /dev/null
+++ b/tests/e2e/cmux_test.go
@@ -0,0 +1,203 @@
+// Copyright 2023 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// These tests are directly validating etcd connection multiplexing.
+//go:build !cluster_proxy
+
+package e2e
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/prometheus/common/expfmt"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
+	"go.etcd.io/etcd/api/v3/mvccpb"
+	"go.etcd.io/etcd/api/v3/version"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp"
+	"go.etcd.io/etcd/tests/v3/framework/config"
+	"go.etcd.io/etcd/tests/v3/framework/e2e"
+)
+
+func TestConnectionMultiplexing(t *testing.T) {
+	e2e.BeforeTest(t)
+	for _, tc := range []struct {
+		name      string
+		serverTLS e2e.ClientConnType
+	}{
+		{
+			name:      "ServerTLS",
+			serverTLS: e2e.ClientTLS,
+		},
+		{
+			name:      "ServerNonTLS",
+			serverTLS: e2e.ClientNonTLS,
+		},
+		{
+			name:      "ServerTLSAndNonTLS",
+			serverTLS: e2e.ClientTLSAndNonTLS,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			ctx := context.Background()
+			cfg := e2e.EtcdProcessClusterConfig{ClusterSize: 1, Client: e2e.ClientConfig{ConnectionType: tc.serverTLS}}
+			clus, err := e2e.NewEtcdProcessCluster(ctx, t, e2e.WithConfig(&cfg))
+			require.NoError(t, err)
+			defer clus.Close()
+
+			var clientScenarios []e2e.ClientConnType
+			switch tc.serverTLS {
+			case e2e.ClientTLS:
+				clientScenarios = []e2e.ClientConnType{e2e.ClientTLS}
+			case e2e.ClientNonTLS:
+				clientScenarios = []e2e.ClientConnType{e2e.ClientNonTLS}
+			case e2e.ClientTLSAndNonTLS:
+				clientScenarios = []e2e.ClientConnType{e2e.ClientTLS, e2e.ClientNonTLS}
+			}
+
+			for _, clientTLS := range clientScenarios {
+				name := "ClientNonTLS"
+				if clientTLS == e2e.ClientTLS {
+					name = "ClientTLS"
+				}
+				t.Run(name, func(t *testing.T) {
+					testConnectionMultiplexing(t, ctx, clus.EndpointsV3()[0], clientTLS)
+				})
+			}
+		})
+	}
+
+}
+
+func testConnectionMultiplexing(t *testing.T, ctx context.Context, endpoint string, connType e2e.ClientConnType) {
+	switch connType {
+	case e2e.ClientTLS:
+		endpoint = e2e.ToTLS(endpoint)
+	case e2e.ClientNonTLS:
+	default:
+		panic(fmt.Sprintf("Unsupported conn type %v", connType))
+	}
+	t.Run("etcdctl", func(t *testing.T) {
+		etcdctl, err := e2e.NewEtcdctl(e2e.ClientConfig{ConnectionType: connType}, []string{endpoint})
+		require.NoError(t, err)
+		_, err = etcdctl.Get(ctx, "a", config.GetOptions{})
+		assert.NoError(t, err)
+	})
+	t.Run("clientv3", func(t *testing.T) {
+		c := newClient(t, []string{endpoint}, e2e.ClientConfig{ConnectionType: connType})
+		_, err := c.Get(ctx, "a")
+		assert.NoError(t, err)
+	})
+	t.Run("curl", func(t *testing.T) {
+		for _, httpVersion := range []string{"2", "1.1", "1.0", ""} {
+			tname := "http" + httpVersion
+			if httpVersion == "" {
+				tname = "default"
+			}
+			t.Run(tname, func(t *testing.T) {
+				assert.NoError(t, fetchGrpcGateway(endpoint, httpVersion, connType))
+				assert.NoError(t, fetchMetrics(endpoint, httpVersion, connType))
+				assert.NoError(t, fetchVersion(endpoint, httpVersion, connType))
+				assert.NoError(t, fetchHealth(endpoint, httpVersion, connType))
+				assert.NoError(t, fetchDebugVars(endpoint, httpVersion, connType))
+			})
+		}
+	})
+}
+
+func fetchGrpcGateway(endpoint string, httpVersion string, connType e2e.ClientConnType) error {
+	rangeData, err := json.Marshal(&pb.RangeRequest{
+		Key: []byte("a"),
+	})
+	if err != nil {
+		return err
+	}
+	req := e2e.CURLReq{Endpoint: "/v3/kv/range", Value: string(rangeData), Timeout: 5, HttpVersion: httpVersion}
+	respData, err := curl(endpoint, "POST", req, connType)
+	return validateGrpcgatewayRangeReponse([]byte(respData))
+}
+
+func validateGrpcgatewayRangeReponse(respData []byte) error {
+	// Modified json annotation so ResponseHeader fields are stored in string.
+	type responseHeader struct {
+		ClusterId uint64 `json:"cluster_id,string,omitempty"`
+		MemberId  uint64 `json:"member_id,string,omitempty"`
+		Revision  int64  `json:"revision,string,omitempty"`
+		RaftTerm  uint64 `json:"raft_term,string,omitempty"`
+	}
+	type rangeResponse struct {
+		Header *responseHeader    `json:"header,omitempty"`
+		Kvs    []*mvccpb.KeyValue `json:"kvs,omitempty"`
+		More   bool               `json:"more,omitempty"`
+		Count  int64              `json:"count,omitempty"`
+	}
+	var resp rangeResponse
+	return json.Unmarshal(respData, &resp)
+}
+
+func fetchMetrics(endpoint string, httpVersion string, connType e2e.ClientConnType) error {
+	req := e2e.CURLReq{Endpoint: "/metrics", Timeout: 5, HttpVersion: httpVersion}
+	respData, err := curl(endpoint, "GET", req, connType)
+	if err != nil {
+		return err
+	}
+	var parser expfmt.TextParser
+	_, err = parser.TextToMetricFamilies(strings.NewReader(strings.ReplaceAll(respData, "\r\n", "\n")))
+	return err
+}
+
+func fetchVersion(endpoint string, httpVersion string, connType e2e.ClientConnType) error {
+	req := e2e.CURLReq{Endpoint: "/version", Timeout: 5, HttpVersion: httpVersion}
+	respData, err := curl(endpoint, "GET", req, connType)
+	if err != nil {
+		return err
+	}
+	var resp version.Versions
+	return json.Unmarshal([]byte(respData), &resp)
+}
+
+func fetchHealth(endpoint string, httpVersion string, connType e2e.ClientConnType) error {
+	req := e2e.CURLReq{Endpoint: "/health", Timeout: 5, HttpVersion: httpVersion}
+	respData, err := curl(endpoint, "GET", req, connType)
+	if err != nil {
+		return err
+	}
+	var resp etcdhttp.Health
+	return json.Unmarshal([]byte(respData), &resp)
+}
+
+func fetchDebugVars(endpoint string, httpVersion string, connType e2e.ClientConnType) error {
+	req := e2e.CURLReq{Endpoint: "/debug/vars", Timeout: 5, HttpVersion: httpVersion}
+	respData, err := curl(endpoint, "GET", req, connType)
+	if err != nil {
+		return err
+	}
+	var resp map[string]interface{}
+	return json.Unmarshal([]byte(respData), &resp)
+}
+
+func curl(endpoint string, method string, curlReq e2e.CURLReq, connType e2e.ClientConnType) (string, error) {
+	args := e2e.CURLPrefixArgs(endpoint, e2e.ClientConfig{ConnectionType: connType}, false, method, curlReq)
+	lines, err := e2e.RunUtilCompletion(args, nil)
+	if err != nil {
+		return "", err
+	}
+	return strings.Join(lines, "\n"), nil
+}
diff --git a/tests/go.mod b/tests/go.mod
index 6897b664d..23e29292a 100644
--- a/tests/go.mod
+++ b/tests/go.mod
@@ -21,6 +21,7 @@ require (
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/grpc-ecosystem/grpc-gateway v1.16.0
 	github.com/prometheus/client_golang v1.14.0
+	github.com/prometheus/common v0.37.0
 	github.com/soheilhy/cmux v0.1.5
 	github.com/stretchr/testify v1.8.2
 	go.etcd.io/etcd/api/v3 v3.6.0-alpha.0
@@ -75,7 +76,6 @@ require (
 	github.com/olekukonko/tablewriter v0.0.5 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_model v0.3.0 // indirect
-	github.com/prometheus/common v0.37.0 // indirect
 	github.com/prometheus/procfs v0.8.0 // indirect
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/sirupsen/logrus v1.8.1 // indirect