diff --git a/source/text/implementation/vss-implementation-text_handlers-utf8-dynamic.adb b/source/text/implementation/vss-implementation-text_handlers-utf8-dynamic.adb
index 5f71b3f7..06f61adb 100644
--- a/source/text/implementation/vss-implementation-text_handlers-utf8-dynamic.adb
+++ b/source/text/implementation/vss-implementation-text_handlers-utf8-dynamic.adb
@@ -576,7 +576,9 @@ package body VSS.Implementation.Text_Handlers.UTF8.Dynamic is
          return;
       end if;
 
-      Unchecked_Forward (Self.Pointer.Storage, After);
+      if To.Index <= Self.Length then
+         Unchecked_Forward (Self.Pointer.Storage, After);
+      end if;
 
       Size   := After.UTF8_Offset - From.UTF8_Offset;
       Length := After.Index - From.Index;
diff --git a/source/text/implementation/vss-implementation-text_handlers-utf8-static.adb b/source/text/implementation/vss-implementation-text_handlers-utf8-static.adb
index 58f6664e..1e4a5e83 100644
--- a/source/text/implementation/vss-implementation-text_handlers-utf8-static.adb
+++ b/source/text/implementation/vss-implementation-text_handlers-utf8-static.adb
@@ -515,7 +515,9 @@ package body VSS.Implementation.Text_Handlers.UTF8.Static is
          return;
       end if;
 
-      Unchecked_Forward (Self.Storage, After);
+      if To.Index <= Self.Length then
+         Unchecked_Forward (Self.Storage, After);
+      end if;
 
       Size   := After.UTF8_Offset - From.UTF8_Offset;
       Length := After.Index - From.Index;