diff --git a/mod/forum/post.php b/mod/forum/post.php
index a6c48b00dd1..aed80512ca5 100644
--- a/mod/forum/post.php
+++ b/mod/forum/post.php
@@ -87,9 +87,10 @@ if (!isloggedin() or isguestuser()) {
     $PAGE->set_context($modcontext);
     $PAGE->set_title($course->shortname);
     $PAGE->set_heading($course->fullname);
+    $referer = clean_param(get_referer(false), PARAM_LOCALURL);
 
     echo $OUTPUT->header();
-    echo $OUTPUT->confirm(get_string('noguestpost', 'forum').'<br /><br />'.get_string('liketologin'), get_login_url(), get_referer(false));
+    echo $OUTPUT->confirm(get_string('noguestpost', 'forum').'<br /><br />'.get_string('liketologin'), get_login_url(), $referer);
     echo $OUTPUT->footer();
     exit;
 }
diff --git a/mod/quiz/renderer.php b/mod/quiz/renderer.php
index 01dfa5d80b5..9772d452c2c 100644
--- a/mod/quiz/renderer.php
+++ b/mod/quiz/renderer.php
@@ -850,8 +850,8 @@ class mod_quiz_renderer extends plugin_renderer_base {
         $output .= $this->view_information($quiz, $cm, $context, $messages);
         $guestno = html_writer::tag('p', get_string('guestsno', 'quiz'));
         $liketologin = html_writer::tag('p', get_string('liketologin'));
-        $output .= $this->confirm($guestno."\n\n".$liketologin."\n", get_login_url(),
-                get_referer(false));
+        $referer = clean_param(get_referer(false), PARAM_LOCALURL);
+        $output .= $this->confirm($guestno."\n\n".$liketologin."\n", get_login_url(), $referer);
         return $output;
     }