diff --git a/src/vars.c b/src/vars.c
index 9be146e..130e98b 100644
--- a/src/vars.c
+++ b/src/vars.c
@@ -815,7 +815,7 @@
 	}
 
 	rule->arg.vars.expr = sample_parse_expr((char **)args, arg, px->conf.args.file,
-	                                        px->conf.args.line, err, &px->conf.args, NULL);
+	                                        px->conf.args.line, err, (px->cap & PR_CAP_DEF) ? NULL: &px->conf.args, NULL);
 	if (!rule->arg.vars.expr)
 		return ACT_RET_PRS_ERR;