diff --git a/pptx/oxml/__init__.py b/pptx/oxml/__init__.py
index f115df266..4a4310f59 100644
--- a/pptx/oxml/__init__.py
+++ b/pptx/oxml/__init__.py
@@ -11,12 +11,16 @@
 
 from lxml import etree
 
+from defusedxml.ElementTree import XMLParser
+
 from .ns import NamespacePrefixedTag
 
+defusedxml.defuse_stdlib()
+
 
 # configure etree XML parser -------------------------------
 element_class_lookup = etree.ElementNamespaceClassLookup()
-oxml_parser = etree.XMLParser(remove_blank_text=True, resolve_entities=False)
+oxml_parser = XMLParser(remove_blank_text=True, resolve_entities=False)
 oxml_parser.set_element_class_lookup(element_class_lookup)