diff --git a/htdocs/feed.php b/htdocs/feed.php
index 0b47af4d..7e40b511 100644
--- a/htdocs/feed.php
+++ b/htdocs/feed.php
@@ -20,7 +20,7 @@ $request = new CalDAVRequest();
  * Source: http://stackoverflow.com/questions/1960461/convert-plain-text-hyperlinks-into-html-hyperlinks-in-php
  */
 function hyperlink( $text ) {
-  return preg_replace( '@(https?://([-\w\.]+[-\w])+(:\d+)?(/([\w/_\.#-]*(\?\S+)?[^\.\s])?)?)@', '<a href="$1" target="_blank">$1</a>', $text );
+  return preg_replace( '@(https?://([-\w\.]+[-\w])+(:\d+)?(/([\w/_\.#-]*(\?\S+)?[^\.\s])?)?)@', '<a href="$1" target="_blank">$1</a>', htmlspecialchars($text) );
 }
 
 function caldav_get_feed( $request ) {