- Fix possible infinite redirect on attachment preview (#1488199)

CHANGELOG

@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix possible infinite redirect on attachment preview (#1488199)
 - Improved clickjacking protection for browsers which don't support X-Frame-Options headers
 - Fixed bug where similiar folder names were highlighted wrong (#1487860)
 - Fixed bug in handling link with '!' character in it (#1488195)

program/steps/mail/get.inc

@@ -22,7 +22,7 @@
 
 // show loading page
 if (!empty($_GET['_preload'])) {
-  $url = str_replace('&_preload=1', '', $_SERVER['REQUEST_URI']);
+  $url = preg_replace('/[&?]+_preload=1/', '', $_SERVER['REQUEST_URI']);
   $message = rcube_label('loadingdata');
 
   header('Content-Type: text/html; charset=' . RCMAIL_CHARSET);