diff --git a/mod/bigbluebuttonbn/classes/local/helpers/files.php b/mod/bigbluebuttonbn/classes/local/helpers/files.php
index dddce8d1b520a..19730cd3779fb 100644
--- a/mod/bigbluebuttonbn/classes/local/helpers/files.php
+++ b/mod/bigbluebuttonbn/classes/local/helpers/files.php
@@ -251,9 +251,12 @@ public static function get_plugin_filename(?stdClass $course, ?stdClass $cm, con
         } else {
             require_login(null, true, $cm, true, true);
         }
-        if (!has_capability('mod/bigbluebuttonbn:join', $context)) {
+
+        // If the file belongs to a course module, ensure user can join the activity.
+        if ($cm !== null && !has_capability('mod/bigbluebuttonbn:join', $context)) {
             return null;
         }
+
         return implode('/', $args);
     }