diff --git a/websockets-jsr/src/main/java/io/undertow/websockets/jsr/JsrWebSocketMessages.java b/websockets-jsr/src/main/java/io/undertow/websockets/jsr/JsrWebSocketMessages.java
index 97f9a45012..1b3d621469 100644
--- a/websockets-jsr/src/main/java/io/undertow/websockets/jsr/JsrWebSocketMessages.java
+++ b/websockets-jsr/src/main/java/io/undertow/websockets/jsr/JsrWebSocketMessages.java
@@ -86,7 +86,7 @@ public interface JsrWebSocketMessages {
     @Message(id = 3015, value = "No decoder accepted message %s")
     String noDecoderAcceptedMessage(List<? extends Decoder> decoders);
 
-    @Message(id = 3016, value = "Cannot send in middle of fragmeneted message")
+    @Message(id = 3016, value = "Cannot send in middle of fragmented message")
     IllegalStateException cannotSendInMiddleOfFragmentedMessage();
 
     @Message(id = 3017, value = "Cannot add endpoint after deployment")
diff --git a/websockets-jsr/src/main/java/io/undertow/websockets/jsr/WebSocketSessionRemoteEndpoint.java b/websockets-jsr/src/main/java/io/undertow/websockets/jsr/WebSocketSessionRemoteEndpoint.java
index ff628e93f6..5015958cba 100644
--- a/websockets-jsr/src/main/java/io/undertow/websockets/jsr/WebSocketSessionRemoteEndpoint.java
+++ b/websockets-jsr/src/main/java/io/undertow/websockets/jsr/WebSocketSessionRemoteEndpoint.java
@@ -17,24 +17,24 @@
  */
 package io.undertow.websockets.jsr;
 
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.Future;
+
 import io.undertow.websockets.core.BinaryOutputStream;
 import io.undertow.websockets.core.StreamSinkFrameChannel;
 import io.undertow.websockets.core.WebSocketCallback;
 import io.undertow.websockets.core.WebSocketFrameType;
 import io.undertow.websockets.core.WebSocketUtils;
 import io.undertow.websockets.core.WebSockets;
-import org.xnio.channels.Channels;
-
 import jakarta.websocket.EncodeException;
 import jakarta.websocket.RemoteEndpoint;
 import jakarta.websocket.SendHandler;
-import java.io.IOException;
-import java.io.OutputStream;
-import java.io.OutputStreamWriter;
-import java.io.Writer;
-import java.nio.ByteBuffer;
-import java.nio.charset.StandardCharsets;
-import java.util.concurrent.Future;
+import org.xnio.channels.Channels;
 
 /**
  * {@link RemoteEndpoint} implementation which uses a WebSocketSession for all its operation.
@@ -243,7 +243,7 @@ class BasicWebSocketSessionRemoteEndpoint implements Basic {
         private StreamSinkFrameChannel binaryFrameSender;
         private StreamSinkFrameChannel textFrameSender;
 
-        public void assertNotInFragment() {
+        public synchronized void assertNotInFragment() {
             if (textFrameSender != null || binaryFrameSender != null) {
                 throw JsrWebSocketMessages.MESSAGES.cannotSendInMiddleOfFragmentedMessage();
             }
@@ -268,57 +268,78 @@ public void sendBinary(final ByteBuffer data) throws IOException {
             data.clear(); //for some reason the TCK expects this, might as well just match the RI behaviour
         }
 
-        @Override
+       @Override
         public void sendText(final String partialMessage, final boolean isLast) throws IOException {
-            if(partialMessage == null) {
+            if (partialMessage == null) {
                 throw JsrWebSocketMessages.MESSAGES.messageInNull();
             }
-            if (binaryFrameSender != null) {
-                throw JsrWebSocketMessages.MESSAGES.cannotSendInMiddleOfFragmentedMessage();
-            }
-            if (textFrameSender == null) {
-                textFrameSender = undertowSession.getWebSocketChannel().send(WebSocketFrameType.TEXT);
-            }
+
+            StreamSinkFrameChannel sender = getTextFrameSender();
+
             try {
-                Channels.writeBlocking(textFrameSender, WebSocketUtils.fromUtf8String(partialMessage));
-                if(isLast) {
-                    textFrameSender.shutdownWrites();
+                Channels.writeBlocking(sender, WebSocketUtils.fromUtf8String(partialMessage));
+                if (isLast) {
+                    sender.shutdownWrites();
                 }
-                Channels.flushBlocking(textFrameSender);
+                Channels.flushBlocking(sender);
             } finally {
                 if (isLast) {
-                    textFrameSender = null;
+                    clearTextFrameSender();
                 }
             }
-
         }
 
         @Override
         public void sendBinary(final ByteBuffer partialByte, final boolean isLast) throws IOException {
-
             if(partialByte == null) {
                 throw JsrWebSocketMessages.MESSAGES.messageInNull();
             }
-            if (textFrameSender != null) {
-                throw JsrWebSocketMessages.MESSAGES.cannotSendInMiddleOfFragmentedMessage();
-            }
-            if (binaryFrameSender == null) {
-                binaryFrameSender = undertowSession.getWebSocketChannel().send(WebSocketFrameType.BINARY);
-            }
+
+            StreamSinkFrameChannel sender = getBinaryFrameSender();
+
             try {
-                Channels.writeBlocking(binaryFrameSender, partialByte);
-                if(isLast) {
-                    binaryFrameSender.shutdownWrites();
+                Channels.writeBlocking(sender, partialByte);
+                if (isLast) {
+                    sender.shutdownWrites();
                 }
-                Channels.flushBlocking(binaryFrameSender);
-            } finally {
+                Channels.flushBlocking(sender);
+            }
+            finally {
                 if (isLast) {
-                    binaryFrameSender = null;
+                    clearBinaryFrameSender();
                 }
             }
             partialByte.clear();
         }
 
+        private synchronized StreamSinkFrameChannel getTextFrameSender() throws IOException {
+            if (binaryFrameSender != null) {
+                throw JsrWebSocketMessages.MESSAGES.cannotSendInMiddleOfFragmentedMessage();
+            }
+            if (textFrameSender == null) {
+                textFrameSender = undertowSession.getWebSocketChannel().send(WebSocketFrameType.TEXT);
+            }
+            return textFrameSender;
+        }
+
+        private synchronized void clearTextFrameSender() {
+            textFrameSender = null;
+        }
+
+        private synchronized StreamSinkFrameChannel getBinaryFrameSender() throws IOException {
+            if (textFrameSender != null) {
+                throw JsrWebSocketMessages.MESSAGES.cannotSendInMiddleOfFragmentedMessage();
+            }
+            if (binaryFrameSender == null) {
+                binaryFrameSender = undertowSession.getWebSocketChannel().send(WebSocketFrameType.BINARY);
+            }
+            return binaryFrameSender;
+        }
+
+        private synchronized void clearBinaryFrameSender() {
+            binaryFrameSender = null;
+        }
+
         @Override
         public OutputStream getSendStream() throws IOException {
             assertNotInFragment();