diff --git a/program/include/rcube_string_replacer.php b/program/include/rcube_string_replacer.php
index 0471dd0dc..326bb7f51 100644
--- a/program/include/rcube_string_replacer.php
+++ b/program/include/rcube_string_replacer.php
@@ -36,13 +36,14 @@ class rcube_string_replacer
   function __construct()
   {
     // Simplified domain expression for UTF8 characters handling
-    $utf_domain = '[^&@"\'\\/\s\r\t\n]+\\.[a-z]{2,5}';
+    $utf_domain = '[^?&@"\'\\/()\s\r\t\n]+\\.[a-z]{2,5}';
+    $url = '[a-z0-9%=#+?.:&\\/_-]+';
 
-    $this->link_pattern = "/([\w]+:\/\/|\Wwww\.)($utf_domain(\S+)?)/i";
+    $this->link_pattern = "/([\w]+:\/\/|\Wwww\.)($utf_domain($url)?)/i";
     $this->mailto_pattern = "/("
         ."[-\w!\#\$%&\'*+~\/^`|{}=]+(?:\.[-\w!\#\$%&\'*+~\/^`|{}=]+)*"  // local-part
         ."@$utf_domain"                                                 // domain-part
-        ."(\?\S+)?"                                                     // e.g. ?subject=test...
+        ."(\?$url)?"                                                     // e.g. ?subject=test...
         .")/i";
   }