- Improve email regexp in mailto: links handler (#1486808)

program/include/rcube_string_replacer.php

@@ -39,7 +39,10 @@ class rcube_string_replacer
     $url_chars_within = '\?\.~,!';
 
     $this->link_pattern = "/([\w]+:\/\/|\Wwww\.)([a-z0-9\-\.]+[a-z]{2,4}([$url_chars$url_chars_within]*[$url_chars])?)/i";
-    $this->mailto_pattern = "/([a-z0-9][a-z0-9\-\.\+\_]*@([a-z0-9]([-a-z0-9]*[a-z0-9])?\\.)+[a-z]{2,5})/i";
+    $this->mailto_pattern = "/("
+        ."[-\w!\#\$%&\'*+~\/^`|{}=]+(?:\.[-\w!\#\$%&\'*+~\/^`|{}=]+)*"  // local-part
+        ."@([a-z0-9]([-a-z0-9]*[a-z0-9])?\\.)+[a-z]{2,5}"               // domain-part
+        .")/i";
   }
 
   /**