diff --git a/Modules/expat/xmlparse.c b/Modules/expat/xmlparse.c
index e04426d..105958b 100644
--- a/Modules/expat/xmlparse.c
+++ b/Modules/expat/xmlparse.c
@@ -3682,6 +3682,9 @@
         return XML_ERROR_UNCLOSED_TOKEN;
       case XML_TOK_PARTIAL_CHAR:
         return XML_ERROR_PARTIAL_CHAR;
+      case -XML_TOK_PROLOG_S:
+        tok = -tok;
+        break;
       case XML_TOK_NONE:
 #ifdef XML_DTD
         /* for internal PE NOT referenced between declarations */