diff --git a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightFieldTests.java b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightFieldTests.java
index 6fb53c2ed1da0..d3d7c1aa8d411 100644
--- a/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightFieldTests.java
+++ b/server/src/test/java/org/opensearch/search/fetch/subphase/highlight/HighlightFieldTests.java
@@ -53,19 +53,32 @@ public class HighlightFieldTests extends OpenSearchTestCase {
 
     public static HighlightField createTestItem() {
         String name = frequently() ? randomAlphaOfLengthBetween(5, 20) : randomRealisticUnicodeOfCodepointLengthBetween(5, 20);
+        name = replaceUnicodeControlCharacters(name);
         Text[] fragments = null;
         if (frequently()) {
             int size = randomIntBetween(0, 5);
             fragments = new Text[size];
             for (int i = 0; i < size; i++) {
-                fragments[i] = new Text(
-                    frequently() ? randomAlphaOfLengthBetween(10, 30) : randomRealisticUnicodeOfCodepointLengthBetween(10, 30)
-                );
+                String fragmentText = frequently()
+                    ? randomAlphaOfLengthBetween(10, 30)
+                    : randomRealisticUnicodeOfCodepointLengthBetween(10, 30);
+                fragmentText = replaceUnicodeControlCharacters(fragmentText);
+                fragments[i] = new Text(fragmentText);
             }
         }
         return new HighlightField(name, fragments);
     }
 
+    public void testReplaceUnicodeControlCharacters() {
+        assertEquals("æÆ ¢¡Èýñ«Ò", replaceUnicodeControlCharacters("æÆ\u0000¢¡Èýñ«Ò"));
+        assertEquals("test_string_without_control_characters", replaceUnicodeControlCharacters("test_string_without_control_characters"));
+        assertEquals("æÆ@¢¡Èýñ«Ò", replaceUnicodeControlCharacters("æÆ\u0000¢¡Èýñ«Ò", "@"));
+        assertEquals(
+            "test_string_without_control_characters",
+            replaceUnicodeControlCharacters("test_string_without_control_characters", "@")
+        );
+    }
+
     public void testFromXContent() throws IOException {
         HighlightField highlightField = createTestItem();
         XContentType xcontentType = randomFrom(XContentType.values());
diff --git a/test/framework/src/main/java/org/opensearch/test/OpenSearchTestCase.java b/test/framework/src/main/java/org/opensearch/test/OpenSearchTestCase.java
index d4090fdfdfdad..904f30a2edf95 100644
--- a/test/framework/src/main/java/org/opensearch/test/OpenSearchTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/OpenSearchTestCase.java
@@ -883,6 +883,15 @@ public static String randomRealisticUnicodeOfCodepointLength(int codePoints) {
         return RandomizedTest.randomRealisticUnicodeOfCodepointLength(codePoints);
     }
 
+    public static String replaceUnicodeControlCharacters(String uniCodeStr, String toReplaceWith) {
+        // replace control characters (https://stackoverflow.com/questions/3438854/replace-unicode-control-characters/)
+        return uniCodeStr.replaceAll("\\p{Cc}", toReplaceWith);
+    }
+
+    public static String replaceUnicodeControlCharacters(String uniCodeStr) {
+        return replaceUnicodeControlCharacters(uniCodeStr, " ");
+    }
+
     /**
      * @param maxArraySize The maximum number of elements in the random array
      * @param stringSize The length of each String in the array