diff --git a/libraries/src/Form/Form.php b/libraries/src/Form/Form.php
index e46b8420b2e5e..a25b7a0bdff10 100644
--- a/libraries/src/Form/Form.php
+++ b/libraries/src/Form/Form.php
@@ -2066,14 +2066,18 @@ protected function validateField(\SimpleXMLElement $element, $group = null, $val
 
 		// Check if the field is required.
 		$required = ((string) $element['required'] == 'true' || (string) $element['required'] == 'required');
-		$disabled = ((string) $element['disabled'] == 'true' || (string) $element['disabled'] == 'disabled');
 
-		$fieldExistsInRequestData = $input->exists((string) $element['name']) || $input->exists($group . '.' . (string) $element['name']);
-
-		// If the field is disabled but it is passed in the request this is invalid as disabled fields are not added to the request
-		if ($disabled && $fieldExistsInRequestData)
+		if ($input)
 		{
-			return new \RuntimeException(\JText::sprintf('JLIB_FORM_VALIDATE_FIELD_INVALID', $element['name']));
+			$disabled = ((string) $element['disabled'] == 'true' || (string) $element['disabled'] == 'disabled');
+
+			$fieldExistsInRequestData = $input->exists((string) $element['name']) || $input->exists($group . '.' . (string) $element['name']);
+
+			// If the field is disabled but it is passed in the request this is invalid as disabled fields are not added to the request
+			if ($disabled && $fieldExistsInRequestData)
+			{
+				return new \RuntimeException(\JText::sprintf('JLIB_FORM_VALIDATE_FIELD_INVALID', $element['name']));
+			}
 		}
 
 		if ($required)