diff --git a/lib/common.lib.php b/lib/common.lib.php
index b9aa44fb4..925c346da 100644
--- a/lib/common.lib.php
+++ b/lib/common.lib.php
@@ -555,6 +555,7 @@ function html_purifier($html)
     $config->set('HTML.SafeObject', true);
     $config->set('HTML.SafeIframe', true);
     $config->set('URI.SafeIframeRegexp','%^(https?:)?//('.$safeiframe.')%');
+    $config->set('Attr.AllowedFrameTargets', array('_blank'));
     $purifier = new HTMLPurifier($config);
     return $purifier->purify($html);
 }