diff --git a/CHANGELOG.rdoc b/CHANGELOG.rdoc
index 9dfe4b4606..d4b59ab731 100644
--- a/CHANGELOG.rdoc
+++ b/CHANGELOG.rdoc
@@ -3,6 +3,7 @@
 * Bugfixes
 
   * (JRuby) Fix "null document" error when parsing an empty IO in jruby 1.7.3. #883
+  * (MRI) Fix segfault when there is no default subelement for an HTML node. #917
 
 * Minor Enhancements
 
diff --git a/ext/nokogiri/html_element_description.c b/ext/nokogiri/html_element_description.c
index b0f7094101..696ed9a513 100644
--- a/ext/nokogiri/html_element_description.c
+++ b/ext/nokogiri/html_element_description.c
@@ -86,7 +86,10 @@ static VALUE default_sub_element(VALUE self)
   htmlElemDesc * description;
   Data_Get_Struct(self, htmlElemDesc, description);
 
-  return NOKOGIRI_STR_NEW2(description->defaultsubelt);
+  if (description->defaultsubelt)
+    return NOKOGIRI_STR_NEW2(description->defaultsubelt);
+
+  return Qnil;
 }
 
 /*
diff --git a/test/html/test_element_description.rb b/test/html/test_element_description.rb
index 38ce55c233..8e0a1e908c 100644
--- a/test/html/test_element_description.rb
+++ b/test/html/test_element_description.rb
@@ -69,6 +69,11 @@ def test_default_sub_element
         assert_equal 'div', ElementDescription['body'].default_sub_element
       end
 
+      def test_null_default_sub_element
+        doc = Nokogiri::HTML('foo')
+        doc.root.description.default_sub_element
+      end
+
       def test_optional_attributes
         attrs = ElementDescription['table'].optional_attributes
         assert attrs