diff --git a/wp-includes/class-wp-widget-factory.php b/wp-includes/class-wp-widget-factory.php
index 9b9214e238..ae721542dd 100644
--- a/wp-includes/class-wp-widget-factory.php
+++ b/wp-includes/class-wp-widget-factory.php
@@ -45,6 +45,50 @@ class WP_Widget_Factory {
 		self::__construct();
 	}
 
+	/**
+	 * Memory for the number of times unique class instances have been hashed.
+	 *
+	 * This can be eliminated in favor of straight spl_object_hash() when 5.3
+	 * is the minimum requirement for PHP.
+	 *
+	 * @since 4.6.0
+	 * @access private
+	 * @see WP_Widget_Factory::hash_object()
+	 *
+	 * @var array
+	 */
+	private $hashed_class_counts = array();
+
+	/**
+	 * Hash an object, doing fallback of `spl_object_hash()` if not available.
+	 *
+	 * This can be eliminated in favor of straight spl_object_hash() when 5.3
+	 * is the minimum requirement for PHP.
+	 *
+	 * @since 4.6.0
+	 * @access private
+	 *
+	 * @param WP_Widget $widget Widget.
+	 * @return string Object hash.
+	 */
+	private function hash_object( $widget ) {
+		if ( function_exists( 'spl_object_hash' ) ) {
+			return spl_object_hash( $widget );
+		} else {
+			$class_name = get_class( $widget );
+			$hash = $class_name;
+			if ( ! isset( $widget->_wp_widget_factory_hash_id ) ) {
+				if ( ! isset( $this->hashed_class_counts[ $class_name ] ) ) {
+					$this->hashed_class_counts[ $class_name ] = 0;
+				}
+				$this->hashed_class_counts[ $class_name ] += 1;
+				$widget->_wp_widget_factory_hash_id = $this->hashed_class_counts[ $class_name ];
+			}
+			$hash .= ':' . $widget->_wp_widget_factory_hash_id;
+			return $hash;
+		}
+	}
+
 	/**
 	 * Registers a widget subclass.
 	 *
@@ -56,7 +100,7 @@ class WP_Widget_Factory {
 	 */
 	public function register( $widget ) {
 		if ( $widget instanceof WP_Widget ) {
-			$this->widgets[ spl_object_hash( $widget ) ] = $widget;
+			$this->widgets[ $this->hash_object( $widget ) ] = $widget;
 		} else {
 			$this->widgets[ $widget ] = new $widget();
 		}
@@ -73,7 +117,7 @@ class WP_Widget_Factory {
 	 */
 	public function unregister( $widget ) {
 		if ( $widget instanceof WP_Widget ) {
-			unset( $this->widgets[ spl_object_hash( $widget ) ] );
+			unset( $this->widgets[ $this->hash_object( $widget ) ] );
 		} else {
 			unset( $this->widgets[ $widget ] );
 		}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 0dd5cc46e4..d44dc5e2e6 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37332';
+$wp_version = '4.6-alpha-37333';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.