diff --git src/wp-admin/includes/class-wp-plugins-list-table.php src/wp-admin/includes/class-wp-plugins-list-table.php
index 5d0c78f..a8072ad 100644
--- src/wp-admin/includes/class-wp-plugins-list-table.php
+++ src/wp-admin/includes/class-wp-plugins-list-table.php
@@ -515,10 +515,15 @@ class WP_Plugins_List_Table extends WP_List_Table {
 		if ( ! empty( $totals['upgrade'] ) && ! empty( $plugin_data['update'] ) )
 			$class .= ' update';
 
+		$plugin_slug = 'not-hosted-on-official-wordpress-repository';
+		if ( ! empty( $plugin_data['slug'] ) ) {
+			$plugin_slug = $plugin_data['slug'];
+		}
+
 		printf( "<tr id='%s' class='%s' data-slug='%s'>",
 			$id,
 			$class,
-			$plugin_data['slug']
+			esc_attr( $plugin_slug )
 		);
 
 		list( $columns, $hidden ) = $this->get_column_info();