<<<
--- /django__django/django/forms/fields.py
+++ /django__django/django/forms/fields.py
@@ -686,7 +686,10 @@
 
         value = super().to_python(value)
         if value:
-            url_fields = split_url(value)
+            try:
+                url_fields = split_url(value)
+            except ValueError:
+                raise ValidationError(self.error_messages['invalid'], code='invalid')
             if not url_fields[0]:
                 # If no URL scheme given, assume http://
                 url_fields[0] = 'http'
>>>