course/editsection.php is using sesskey.

course/editsection.html

@@ -22,6 +22,7 @@
 </tr>
 </table>
 <input type="hidden" name=id value="<?php echo $form->id ?>">
+<input type="hidden" name=sesskey value="<?php echo $form->sesskey ?>">
 <input type="submit" value="<?php print_string("savechanges") ?>">
 </form>
 </center>

course/editsection.php

@@ -23,7 +23,7 @@
 
 /// If data submitted, then process and store.
 
-    if ($form = data_submitted()) {
+    if ($form = data_submitted() and confirm_sesskey()) {
 
         $timenow = time();
 
@@ -43,6 +43,8 @@
         $form = $section;
     }
 
+    $form->sesskey = !empty($USER->id) ? $USER->sesskey : '';
+
     $usehtmleditor = can_use_html_editor();
 
     $sectionname = get_string("name$course->format");