--- slpd/slpd_predicate.c.orig	2019-06-06 14:12:09.025492155 +0000
+++ slpd/slpd_predicate.c	2019-06-06 14:12:56.605386533 +0000
@@ -2111,6 +2111,10 @@ int SLPDPredicateTestTree(SLPDPredicateT
    if (!parseTree)
       return 1;
 
+   /* a NULL set of attribures is always false */
+   if (!slp_attr)
+      return 0;
+
    err = treeFilter(parseTree, slp_attr);
 
    return (err == FR_EVAL_TRUE);