diff --git a/plugins/transport-reactor-netty4/src/javaRestTest/java/org/opensearch/rest/ReactorNetty4BadRequestIT.java b/plugins/transport-reactor-netty4/src/javaRestTest/java/org/opensearch/rest/ReactorNetty4BadRequestIT.java
index 62834483b5e9b..b1d21fe4eee09 100644
--- a/plugins/transport-reactor-netty4/src/javaRestTest/java/org/opensearch/rest/ReactorNetty4BadRequestIT.java
+++ b/plugins/transport-reactor-netty4/src/javaRestTest/java/org/opensearch/rest/ReactorNetty4BadRequestIT.java
@@ -112,4 +112,16 @@ public void testInvalidHeaderValue() throws IOException {
         assertThat(map.get("type"), equalTo("content_type_header_exception"));
         assertThat(map.get("reason"), equalTo("java.lang.IllegalArgumentException: invalid Content-Type header []"));
     }
+
+    public void testUnsupportedContentType() throws IOException {
+        final Request request = new Request("POST", "/_bulk/stream");
+        final RequestOptions.Builder options = request.getOptions().toBuilder();
+        request.setOptions(options);
+        final ResponseException e = expectThrows(ResponseException.class, () -> client().performRequest(request));
+        final Response response = e.getResponse();
+        assertThat(response.getStatusLine().getStatusCode(), equalTo(406));
+        final ObjectPath objectPath = ObjectPath.createFromResponse(response);
+        final String error = objectPath.evaluate("error");
+        assertThat(error, equalTo("Content-Type header [] is not supported"));
+    }
 }
diff --git a/server/src/main/java/org/opensearch/rest/RestController.java b/server/src/main/java/org/opensearch/rest/RestController.java
index 9889f5d67e966..0d6f965c7033f 100644
--- a/server/src/main/java/org/opensearch/rest/RestController.java
+++ b/server/src/main/java/org/opensearch/rest/RestController.java
@@ -326,8 +326,8 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
 
     private void dispatchRequest(RestRequest request, RestChannel channel, RestHandler handler) throws Exception {
         final int contentLength = request.content().length();
+        final MediaType mediaType = request.getMediaType();
         if (contentLength > 0) {
-            final MediaType mediaType = request.getMediaType();
             if (mediaType == null) {
                 sendContentTypeErrorMessage(request.getAllHeaderValues("Content-Type"), channel);
                 return;
@@ -343,6 +343,7 @@ private void dispatchRequest(RestRequest request, RestChannel channel, RestHandl
                 return;
             }
         }
+
         RestChannel responseChannel = channel;
         try {
             if (handler.canTripCircuitBreaker()) {
@@ -364,6 +365,11 @@ private void dispatchRequest(RestRequest request, RestChannel channel, RestHandl
                             + "]"
                     );
                 }
+
+                if (mediaType == null) {
+                    sendContentTypeErrorMessage(request.getAllHeaderValues("Content-Type"), responseChannel);
+                    return;
+                }
             } else {
                 // if we could reserve bytes for the request we need to send the response also over this channel
                 responseChannel = new ResourceHandlingHttpChannel(channel, circuitBreakerService, contentLength);