diff --git a/CHANGELOG.md b/CHANGELOG.md
index 00e1761ab..4b1a12802 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@
     * Grav 1.6: Fixed `FlexObject::update()` removing fields on save
     * Fixed `mkdir(...)` race condition
     * Fixed `Obtaining write lock failed on file...`
+    * Fixed potential undefined property in `onPageNotFound` event handling
 
 # v1.6.0-rc.3
 ## 02/18/2019
diff --git a/system/src/Grav/Common/Processors/PagesProcessor.php b/system/src/Grav/Common/Processors/PagesProcessor.php
index bb8d44620..8b25255ee 100644
--- a/system/src/Grav/Common/Processors/PagesProcessor.php
+++ b/system/src/Grav/Common/Processors/PagesProcessor.php
@@ -36,7 +36,9 @@ class PagesProcessor extends ProcessorBase
 
         if (!$page->routable()) {
             // If no page found, fire event
-            $event = $this->container->fireEvent('onPageNotFound', new Event(['page' => $page]));
+            $event = new Event(['page' => $page]);
+            $event->page = null;
+            $event = $this->container->fireEvent('onPageNotFound', $event);
 
             if (isset($event->page)) {
                 unset ($this->container['page']);