diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index b084822..152eda6 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -3520,7 +3520,7 @@
 		++p;
 	    p = find_ucmd(eap, p, full, NULL, NULL);
 	}
-	if (p == eap->cmd)
+	if (p == NULL || p == eap->cmd)
 	    eap->cmdidx = CMD_SIZE;
     }
 
diff --git a/src/testdir/test_vim9_cmd.vim b/src/testdir/test_vim9_cmd.vim
index 95d6969..bdc9ad0 100644
--- a/src/testdir/test_vim9_cmd.vim
+++ b/src/testdir/test_vim9_cmd.vim
@@ -701,5 +701,14 @@
   delete('Xfile')
 enddef
 
+def Test_ambiguous_user_cmd()
+  var lines =<< trim END
+      com Cmd1 eval 0
+      com Cmd2 eval 0
+      Cmd
+  END
+  CheckScriptFailure(lines, 'E464:')
+enddef
+
 
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker
diff --git a/src/version.c b/src/version.c
index f28bb4a..a5c7127 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2148,
+/**/
     2147,
 /**/
     2146,