diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
index c3df6ce6..571918d4 100644
--- a/expat/lib/xmlparse.c
+++ b/expat/lib/xmlparse.c
@@ -2034,6 +2034,8 @@ XML_GetCurrentByteIndex(XML_Parser parser)
 int XMLCALL
 XML_GetCurrentByteCount(XML_Parser parser)
 {
+  if (parser == NULL)
+    return 0;
   if (eventEndPtr && eventPtr)
     return (int)(eventEndPtr - eventPtr);
   return 0;