diff --git a/html_xblock/__init__.py b/html_xblock/__init__.py
index c3ffa9d..f3b5cc6 100644
--- a/html_xblock/__init__.py
+++ b/html_xblock/__init__.py
@@ -1,4 +1,4 @@
 """HTML XBlock module."""
 from .html import ExcludedHTML5XBlock, HTML5XBlock
 
-__version__ = "1.3.6"
+__version__ = "1.3.7"
diff --git a/html_xblock/bleaching.py b/html_xblock/bleaching.py
index 801c9ce..46262fe 100644
--- a/html_xblock/bleaching.py
+++ b/html_xblock/bleaching.py
@@ -80,6 +80,8 @@ def _get_allowed_tags(self):
             'u',
             'style',
             'iframe',
+            'details',
+            'summary',
         }
 
         if self.allow_javascript: