diff --git a/wp-includes/taxonomy.php b/wp-includes/taxonomy.php
index 76a9ada576..6374d73bfa 100644
--- a/wp-includes/taxonomy.php
+++ b/wp-includes/taxonomy.php
@@ -337,7 +337,7 @@ function get_taxonomy( $taxonomy ) {
 function taxonomy_exists( $taxonomy ) {
 	global $wp_taxonomies;
 
-	return isset( $wp_taxonomies[ $taxonomy ] );
+	return is_string( $taxonomy ) && isset( $wp_taxonomies[ $taxonomy ] );
 }
 
 /**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 780f239318..2433330603 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-alpha-53868';
+$wp_version = '6.1-alpha-53869';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.