diff --git a/src/Avalonia.Controls/Utils/StringUtils.cs b/src/Avalonia.Controls/Utils/StringUtils.cs
index 6c459d7985..2ea47b442a 100644
--- a/src/Avalonia.Controls/Utils/StringUtils.cs
+++ b/src/Avalonia.Controls/Utils/StringUtils.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Globalization;
 using Avalonia.Media.TextFormatting.Unicode;
 
@@ -122,6 +123,8 @@ namespace Avalonia.Controls.Utils
             {
                 return 0;
             }
+
+            cursor = Math.Min(cursor, text.Length);
             
             int begin;
             int i;