diff --git a/mod/quiz/locallib.php b/mod/quiz/locallib.php
index 47eb0bc6f4e..d4264b704f8 100644
--- a/mod/quiz/locallib.php
+++ b/mod/quiz/locallib.php
@@ -372,6 +372,11 @@ function quiz_delete_attempt($attempt, $quiz) {
         return;
     }
 
+    if (!isset($quiz->cmid)) {
+        $cm = get_coursemodule_from_instance('quiz', $quiz->id, $quiz->course);
+        $quiz->cmid = $cm->id;
+    }
+
     question_engine::delete_questions_usage_by_activity($attempt->uniqueid);
     $DB->delete_records('quiz_attempts', array('id' => $attempt->id));
 
diff --git a/mod/quiz/report/attemptsreport.php b/mod/quiz/report/attemptsreport.php
index 2342d8507f2..dca7ee99ab9 100644
--- a/mod/quiz/report/attemptsreport.php
+++ b/mod/quiz/report/attemptsreport.php
@@ -318,6 +318,8 @@ abstract class quiz_attempts_report extends quiz_default_report {
                 continue;
             }
 
+            // Set the course module id before calling quiz_delete_attempt().
+            $quiz->cmid = $cm->id;
             quiz_delete_attempt($attempt, $quiz);
         }
     }