diff --git a/src/document-undo.cpp b/src/document-undo.cpp
index cdde7d96ad11b3fdf06e31fa5c85d602fac28973..44c636df27713378244c2e05e49f303390b88102 100644
--- a/src/document-undo.cpp
+++ b/src/document-undo.cpp
@@ -205,7 +205,7 @@ void Inkscape::DocumentUndo::cancel(SPDocument *doc)
     g_assert (doc->sensitive);
     done(doc, "undozone", "");
     // ensure tere is something to undo (extension crach can do nothing)
-    if (doc->undo.back()->description == "undozone") { 
+    if (!doc->undo.empty() && doc->undo.back()->description == "undozone") { 
         undo(doc);
         clearRedo(doc);
     }
diff --git a/src/live_effects/lpe-fillet-chamfer.cpp b/src/live_effects/lpe-fillet-chamfer.cpp
index 60b7f0e3ea172619623f10230249509cd416f8a6..b23faba33f246e0a009adcf11d78c4a17614faae 100644
--- a/src/live_effects/lpe-fillet-chamfer.cpp
+++ b/src/live_effects/lpe-fillet-chamfer.cpp
@@ -338,8 +338,8 @@ void LPEFilletChamfer::doBeforeEffect(SPLPEItem const *lpeItem)
                 }
             }
             if (pathv.size() > i && !pathv[i].closed()) {
-                nodesatellites[i][0].amount = 0;
-                nodesatellites[i][count_path_nodes(pathv[i]) - 1].amount = 0;
+                nodesatellites[i].front().amount = 0;
+                nodesatellites[i].back().amount = 0;
             }
         } 
         if (!_pathvector_nodesatellites) {