diff --git a/solr/core/src/java/org/apache/solr/handler/configsets/CloneConfigSet.java b/solr/core/src/java/org/apache/solr/handler/configsets/CloneConfigSet.java
index c90a3636563..161fbb3ea12 100644
--- a/solr/core/src/java/org/apache/solr/handler/configsets/CloneConfigSet.java
+++ b/solr/core/src/java/org/apache/solr/handler/configsets/CloneConfigSet.java
@@ -30,6 +30,7 @@
 import org.apache.solr.cloud.ConfigSetCmds;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.params.ConfigSetParams;
+import org.apache.solr.common.util.StrUtils;
 import org.apache.solr.core.CoreContainer;
 import org.apache.solr.jersey.PermissionName;
 import org.apache.solr.request.SolrQueryRequest;
@@ -56,21 +57,26 @@ public SolrJerseyResponse cloneExistingConfigSet(CloneConfigsetRequestBody reque
       throws Exception {
     final var response = instantiateJerseyResponse(SolrJerseyResponse.class);
     SolrIdentifierValidator.validateConfigSetName(requestBody.name);
+    final String baseConfigSetName =
+        StrUtils.isNullOrEmpty(requestBody.baseConfigSet)
+            ? CloneConfigsetRequestBody.DEFAULT_CONFIGSET
+            : requestBody.baseConfigSet;
+
     if (configSetService.checkConfigExists(requestBody.name)) {
       throw new SolrException(
           SolrException.ErrorCode.BAD_REQUEST, "ConfigSet already exists: " + requestBody.name);
     }
 
     // is there a base config that already exists
-    if (!configSetService.checkConfigExists(requestBody.baseConfigSet)) {
+    if (!configSetService.checkConfigExists(baseConfigSetName)) {
       throw new SolrException(
           SolrException.ErrorCode.BAD_REQUEST,
-          "Base ConfigSet does not exist: " + requestBody.baseConfigSet);
+          "Base ConfigSet does not exist: " + baseConfigSetName);
     }
 
     final Map<String, Object> configsetCommandMsg = new HashMap<>();
     configsetCommandMsg.put(NAME, requestBody.name);
-    configsetCommandMsg.put(ConfigSetCmds.BASE_CONFIGSET, requestBody.baseConfigSet);
+    configsetCommandMsg.put(ConfigSetCmds.BASE_CONFIGSET, baseConfigSetName);
     if (requestBody.properties != null) {
       for (Map.Entry<String, Object> e : requestBody.properties.entrySet()) {
         configsetCommandMsg.put(
diff --git a/solr/core/src/test/org/apache/solr/cloud/TestConfigSetsAPI.java b/solr/core/src/test/org/apache/solr/cloud/TestConfigSetsAPI.java
index 6736af93b68..530daf60c8d 100644
--- a/solr/core/src/test/org/apache/solr/cloud/TestConfigSetsAPI.java
+++ b/solr/core/src/test/org/apache/solr/cloud/TestConfigSetsAPI.java
@@ -200,6 +200,30 @@ public void testCreate() throws Exception {
         "solr");
   }
 
+  @Test
+  public void testV2CreateWithoutBaseConfigsetUsesDefault() throws Exception {
+    final String configSetName = "v2ConfigSetNoBase" + System.nanoTime();
+    final String baseUrl = cluster.getJettySolrRunners().get(0).getBaseUrl().toString();
+    try (final SolrClient solrClient = getHttpSolrClient(baseUrl);
+        SolrZkClient zkClient =
+            new SolrZkClient.Builder()
+                .withUrl(cluster.getZkServer().getZkAddress())
+                .withTimeout(AbstractZkTestCase.TIMEOUT, TimeUnit.MILLISECONDS)
+                .withConnTimeOut(AbstractZkTestCase.TIMEOUT, TimeUnit.MILLISECONDS)
+                .build()) {
+      assertFalse(getConfigSetService().checkConfigExists(configSetName));
+
+      final var createRequest = new ConfigsetsApi.CloneExistingConfigSet();
+      createRequest.setName(configSetName);
+      final var response = createRequest.process(solrClient);
+
+      assertNotNull(response);
+      assertEquals(0, response.responseHeader.status);
+      assertTrue(getConfigSetService().checkConfigExists(configSetName));
+      assertTrue(zkClient.exists("/configs/" + configSetName + "/solrconfig.xml"));
+    }
+  }
+
   private void setupBaseConfigSet(String baseConfigSetName, Map<String, String> oldProps)
       throws Exception {
     final Path configDir = getFile("solr").resolve("configsets/configset-2/conf");
diff --git a/solr/core/src/test/org/apache/solr/handler/configsets/CloneConfigSetAPITest.java b/solr/core/src/test/org/apache/solr/handler/configsets/CloneConfigSetAPITest.java
new file mode 100644
index 00000000000..55d7c6681ed
--- /dev/null
+++ b/solr/core/src/test/org/apache/solr/handler/configsets/CloneConfigSetAPITest.java
@@ -0,0 +1,73 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+
+package org.apache.solr.handler.configsets;
+
+import static org.apache.solr.SolrTestCaseJ4.assumeWorkingMockito;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import org.apache.solr.SolrTestCase;
+import org.apache.solr.client.api.model.CloneConfigsetRequestBody;
+import org.apache.solr.common.SolrException;
+import org.apache.solr.core.ConfigSetService;
+import org.apache.solr.core.CoreContainer;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/** Unit tests for {@link CloneConfigSet#cloneExistingConfigSet(CloneConfigsetRequestBody)}. */
+public class CloneConfigSetAPITest extends SolrTestCase {
+
+  private CoreContainer mockCoreContainer;
+  private ConfigSetService mockConfigSetService;
+
+  @BeforeClass
+  public static void ensureWorkingMockito() {
+    assumeWorkingMockito();
+  }
+
+  @Before
+  public void setup() {
+    mockCoreContainer = mock(CoreContainer.class);
+    mockConfigSetService = mock(ConfigSetService.class);
+    when(mockCoreContainer.getConfigSetService()).thenReturn(mockConfigSetService);
+  }
+
+  @Test
+  public void testMissingBaseConfigSetDefaultsToDefaultConfigset() throws Exception {
+    when(mockConfigSetService.checkConfigExists("newconfig")).thenReturn(false);
+    when(mockConfigSetService.checkConfigExists(CloneConfigsetRequestBody.DEFAULT_CONFIGSET))
+        .thenReturn(false);
+
+    final var requestBody = new CloneConfigsetRequestBody();
+    requestBody.name = "newconfig";
+    requestBody.baseConfigSet = null;
+
+    final var api = new CloneConfigSet(mockCoreContainer, null, null);
+    final SolrException ex =
+        assertThrows(SolrException.class, () -> api.cloneExistingConfigSet(requestBody));
+
+    assertEquals(SolrException.ErrorCode.BAD_REQUEST.code, ex.code());
+    assertTrue(
+        ex.getMessage()
+            .contains(
+                "Base ConfigSet does not exist: " + CloneConfigsetRequestBody.DEFAULT_CONFIGSET));
+    verify(mockConfigSetService).checkConfigExists(CloneConfigsetRequestBody.DEFAULT_CONFIGSET);
+  }
+}