Index: php5-5.3.3.1/ext/xsl/xsltprocessor.c
===================================================================
--- php5-5.3.3.1.orig/ext/xsl/xsltprocessor.c	2015-10-18 19:45:28.000000000 +0200
+++ php5-5.3.3.1/ext/xsl/xsltprocessor.c	2015-10-19 10:53:14.000000000 +0200
@@ -214,7 +214,9 @@
 	if (error == 1) {
 		for (i = nargs - 1; i >= 0; i--) {
 			obj = valuePop(ctxt);
-			xmlXPathFreeObject(obj);
+			if (obj) {
+				xmlXPathFreeObject(obj);
+			}
 		}
 		return;
 	}