diff --git a/common/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java b/common/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java
index c9256b0a8f33c..f8d7041933907 100644
--- a/common/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java
+++ b/common/unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java
@@ -703,6 +703,9 @@ public boolean contains(final UTF8String substring) {
    * Returns the byte at (byte) position `byteIndex`. If byte index is invalid, returns 0.
    */
   public byte getByte(int byteIndex) {
+    if (byteIndex < 0 || byteIndex >= numBytes) {
+      return 0;
+    }
     return Platform.getByte(base, offset + byteIndex);
   }