diff --git a/src/wp-admin/includes/menu.php b/src/wp-admin/includes/menu.php
index 3cf4a5fdd6c17..9e7f84250f2f6 100644
--- a/src/wp-admin/includes/menu.php
+++ b/src/wp-admin/includes/menu.php
@@ -368,7 +368,17 @@ function sort_menu( $a, $b ) {
 }
 unset( $last_menu_key );
 
-if ( ! user_can_access_admin_page() ) {
+if ( ! admin_page_exists() ) {
+
+	/**
+	 * Fires when access to an admin page which does not exist.
+	 *
+	 * @since 7.0
+	 */
+	do_action( 'admin_page_not_found' );
+
+	wp_die( __( 'The requested page does not exist.' ), 404 );
+} elseif ( ! user_can_access_admin_page() ) {
 
 	/**
 	 * Fires when access to an admin page is denied.
diff --git a/src/wp-admin/includes/plugin.php b/src/wp-admin/includes/plugin.php
index de1468352b3d9..8e3b7505c2821 100644
--- a/src/wp-admin/includes/plugin.php
+++ b/src/wp-admin/includes/plugin.php
@@ -2130,6 +2130,35 @@ function get_plugin_page_hook( $plugin_page, $parent_page ) {
 	}
 }
 
+/**
+ * Checks if admin page exists, if the user would have the required capabilities.
+ *
+ * @since 7.0.0
+ *
+ * @global string $admin_page_parent The parent slug of the current admin page.
+ * @global string $plugin_page  The plugin page slug being loaded.
+ * @global array  $_registered_pages Array of all registered admin page hooks.
+ *
+ * @return bool True if the admin page exists, false otherwise.
+ */
+function admin_page_exists() {
+	global $admin_page_parent, $plugin_page, $_registered_pages;
+
+	if ( ! isset( $admin_page_parent ) ) {
+		$admin_page_parent = get_admin_page_parent();
+	}
+
+	if ( isset( $plugin_page ) ) {
+		$hookname = get_plugin_page_hookname( $plugin_page, $admin_page_parent );
+
+		if ( ! isset( $_registered_pages[ $hookname ] ) ) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
 /**
  * Gets the hook name for the administrative page of a plugin.
  *
@@ -2175,14 +2204,15 @@ function get_plugin_page_hookname( $plugin_page, $parent_page ) {
  * @global array  $_wp_submenu_nopriv
  * @global string $plugin_page
  * @global array  $_registered_pages
+ * @global string $admin_page_parent
  *
  * @return bool True if the current user can access the admin page, false otherwise.
  */
 function user_can_access_admin_page() {
 	global $pagenow, $menu, $submenu, $_wp_menu_nopriv, $_wp_submenu_nopriv,
-		$plugin_page, $_registered_pages;
+		$plugin_page, $_registered_pages, $admin_page_parent;
 
-	$parent = get_admin_page_parent();
+	$parent = isset( $admin_page_parent ) ? $admin_page_parent : get_admin_page_parent();
 
 	if ( ! isset( $plugin_page ) && isset( $_wp_submenu_nopriv[ $parent ][ $pagenow ] ) ) {
 		return false;
@@ -2195,6 +2225,10 @@ function user_can_access_admin_page() {
 
 		$hookname = get_plugin_page_hookname( $plugin_page, $parent );
 
+		if ( ! admin_page_exists() ) {
+			return false;
+		}
+
 		if ( ! isset( $_registered_pages[ $hookname ] ) ) {
 			return false;
 		}