Index: src/wp-includes/formatting.php
===================================================================
--- src/wp-includes/formatting.php	(revision 26349)
+++ src/wp-includes/formatting.php	(working copy)
@@ -2831,6 +2831,7 @@
  * @return string Sanitized value.
  */
 function sanitize_option($option, $value) {
+	$original_value = $value;
 
 	switch ( $option ) {
 		case 'admin_email' :
@@ -2994,7 +2995,7 @@
 			break;
 	}
 
-	$value = apply_filters("sanitize_option_{$option}", $value, $option);
+	$value = apply_filters("sanitize_option_{$option}", $value, $option, $original_value);
 
 	return $value;
 }