diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index 2a7283afca6..f25e600fd1f 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -348,6 +348,9 @@ Bug Fixes
 * SOLR-8223: Avoid accidentally swallowing OutOfMemoryError (in LeaderInitiatedRecoveryThread.java
   or CoreContainer.java) (Mike Drob via Christine Poerschke)
 
+* SOLR-8255: MiniSolrCloudCluster needs to use a thread-safe list to keep track
+  of its child nodes (Alan Woodward)
+
 Optimizations
 ----------------------
 
diff --git a/solr/test-framework/src/java/org/apache/solr/cloud/MiniSolrCloudCluster.java b/solr/test-framework/src/java/org/apache/solr/cloud/MiniSolrCloudCluster.java
index 7f0c54813ad..205ce8178da 100644
--- a/solr/test-framework/src/java/org/apache/solr/cloud/MiniSolrCloudCluster.java
+++ b/solr/test-framework/src/java/org/apache/solr/cloud/MiniSolrCloudCluster.java
@@ -26,11 +26,11 @@ import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.SortedMap;
 import java.util.concurrent.Callable;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Future;
@@ -89,7 +89,7 @@ public class MiniSolrCloudCluster {
 
   private final ZkTestServer zkServer;
   private final boolean externalZkServer;
-  private final List<JettySolrRunner> jettys = new LinkedList<>();
+  private final List<JettySolrRunner> jettys = new CopyOnWriteArrayList<>();
   private final Path baseDir;
   private final CloudSolrClient solrClient;
   private final JettyConfig jettyConfig;