diff --git a/mod/lesson/view.php b/mod/lesson/view.php
index 90f256dcd15..5407b054b40 100644
--- a/mod/lesson/view.php
+++ b/mod/lesson/view.php
@@ -31,7 +31,7 @@ require_once($CFG->libdir . '/completionlib.php');
 $id      = required_param('id', PARAM_INT);             // Course Module ID
 $pageid  = optional_param('pageid', NULL, PARAM_INT);   // Lesson Page ID
 $edit    = optional_param('edit', -1, PARAM_BOOL);
-$userpassword = optional_param('userpassword','',PARAM_CLEAN);
+$userpassword = optional_param('userpassword','',PARAM_RAW);
 
 $cm = get_coursemodule_from_id('lesson', $id, 0, false, MUST_EXIST);;
 $course = $DB->get_record('course', array('id' => $cm->course), '*', MUST_EXIST);
@@ -76,7 +76,7 @@ if (!$canmanage) {
             }
         } else {
             echo $lessonoutput->header($lesson, $cm);
-            echo $lessonoutput->login_prompt($lesson, optional_param('userpassword', 0, PARAM_CLEAN));
+            echo $lessonoutput->login_prompt($lesson, $userpassword !== '');
             echo $lessonoutput->footer();
             exit();
         }