diff --git a/src/legacy.cpp b/src/legacy.cpp
index bcf9c984d..88227ac09 100644
--- a/src/legacy.cpp
+++ b/src/legacy.cpp
@@ -141,12 +141,14 @@ std::string legacyCheckForDeprecatedVariables ()
   for (it = context.config.begin (); it != context.config.end (); ++it)
   {
     // report.*.limit
-    if (it->first.substr (0, 7) == "report." &&
+    if (it->first.length () > 13 &&
+        it->first.substr (0, 7) == "report." &&
         it->first.substr (it->first.length () - 6) == ".limit")
       deprecated.push_back (it->first);
 
     // report.*.annotaitons
-    if (it->first.substr (0, 7) == "report." &&
+    if (it->first.length () > 19 &&
+        it->first.substr (0, 7) == "report." &&
         it->first.substr (it->first.length () - 12) == ".annotations")
       deprecated.push_back (it->first);