diff --git a/pom.xml b/pom.xml
index 31255ef7d48..8d1ae5b06b8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -122,7 +122,7 @@
       <checkstyle.version>12.3.1</checkstyle.version>
       <mockito.version>5.23.0</mockito.version>
       <jctools.version>4.0.6</jctools.version>
-      <netty.version>4.1.135.Final</netty.version>
+      <netty.version>4.1.136.Final</netty.version>
       <hdrhistogram.version>2.2.2</hdrhistogram.version>
       <curator.version>5.9.0</curator.version>
       <zookeeper.version>3.9.5</zookeeper.version>
diff --git a/tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/mqtt/MQTTTest.java b/tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/mqtt/MQTTTest.java
index 7bb92f92579..03cbcb7a1eb 100644
--- a/tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/mqtt/MQTTTest.java
+++ b/tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/mqtt/MQTTTest.java
@@ -111,7 +111,9 @@ public void configureBroker() throws Exception {
    @Test
    public void testConnectWithLargePassword() throws Exception {
       for (String version : Arrays.asList("3.1", "3.1.1")) {
-         String longString = new String(new char[65535]);
+         // MQTT forbids U+0000 in UTF-8 Encoded Strings (MQTT-1.5.3-2 / MQTT-1.5.4-2).
+         // Netty enforces this more strictly since 4.1.136.
+         String longString = "x".repeat(65535);
 
          BlockingConnection connection = null;
          try {