diff --git a/lib/corereqs.js b/lib/corereqs.js
index eeccf11..57fca8d 100644
--- a/lib/corereqs.js
+++ b/lib/corereqs.js
@@ -221,7 +221,12 @@ function packValueMask(reqname, values)
         masksList.push(valueBit);
         bitmask |= valueBit;
     }
-    masksList.sort();
+
+    /* numeric sort */
+    masksList.sort(function(a, b) {
+      return a - b;
+    });
+
     var args = [];
     for (m in masksList)
     {