diff --git a/lib/compat/wordpress-6.5/fonts/class-wp-rest-font-faces-controller.php b/lib/compat/wordpress-6.5/fonts/class-wp-rest-font-faces-controller.php
index 8a4040e3397e0c..1d65e0f63aab9f 100644
--- a/lib/compat/wordpress-6.5/fonts/class-wp-rest-font-faces-controller.php
+++ b/lib/compat/wordpress-6.5/fonts/class-wp-rest-font-faces-controller.php
@@ -858,7 +858,21 @@ protected function sanitize_src( $value ) {
 		 */
 		protected function handle_font_file_upload( $file ) {
 			add_filter( 'upload_mimes', array( 'WP_Font_Utils', 'get_allowed_font_mime_types' ) );
-			add_filter( 'upload_dir', 'wp_get_font_dir' );
+
+			/*
+			 * Set the upload directory to the fonts directory.
+			 *
+			 * wp_get_font_dir() contains the 'font_dir' hook, whose callbacks are
+			 * likely to call wp_get_upload_dir().
+			 *
+			 * To avoid an infinite loop, don't hook wp_get_font_dir() to 'upload_dir'.
+			 * Instead, just pass its return value to the 'upload_dir' callback.
+			 */
+			$font_dir       = wp_get_font_dir();
+			$set_upload_dir = function () use ( $font_dir ) {
+				return $font_dir;
+			};
+			add_filter( 'upload_dir', $set_upload_dir );
 
 			$overrides = array(
 				'upload_error_handler' => array( $this, 'handle_font_file_upload_error' ),
@@ -875,8 +889,7 @@ protected function handle_font_file_upload( $file ) {
 			);
 
 			$uploaded_file = wp_handle_upload( $file, $overrides );
-
-			remove_filter( 'upload_dir', 'wp_get_font_dir' );
+			remove_filter( 'upload_dir', $set_upload_dir );
 			remove_filter( 'upload_mimes', array( 'WP_Font_Utils', 'get_allowed_font_mime_types' ) );
 
 			return $uploaded_file;
diff --git a/lib/compat/wordpress-6.5/fonts/fonts.php b/lib/compat/wordpress-6.5/fonts/fonts.php
index 3911f61ceaec4b..55dc2d3429af92 100644
--- a/lib/compat/wordpress-6.5/fonts/fonts.php
+++ b/lib/compat/wordpress-6.5/fonts/fonts.php
@@ -201,16 +201,6 @@ function gutenberg_register_font_collections() {
 	 *
 	 * @since 6.5.0
 	 *
-	 * @param array $defaults {
-	 *     Array of information about the upload directory.
-	 *
-	 *     @type string       $path    Base directory and subdirectory or full path to the fonts upload directory.
-	 *     @type string       $url     Base URL and subdirectory or absolute URL to the fonts upload directory.
-	 *     @type string       $subdir  Subdirectory
-	 *     @type string       $basedir Path without subdir.
-	 *     @type string       $baseurl URL path without subdir.
-	 *     @type string|false $error   False or error message.
-	 * }
 	 * @return array $defaults {
 	 *     Array of information about the upload directory.
 	 *
@@ -222,19 +212,20 @@ function gutenberg_register_font_collections() {
 	 *     @type string|false $error   False or error message.
 	 * }
 	 */
-	function wp_get_font_dir( $defaults = array() ) {
+	function wp_get_font_dir() {
 		$site_path = '';
 		if ( is_multisite() && ! ( is_main_network() && is_main_site() ) ) {
 			$site_path = '/sites/' . get_current_blog_id();
 		}
 
-		// Sets the defaults.
-		$defaults['path']    = path_join( WP_CONTENT_DIR, 'fonts' ) . $site_path;
-		$defaults['url']     = untrailingslashit( content_url( 'fonts' ) ) . $site_path;
-		$defaults['subdir']  = '';
-		$defaults['basedir'] = path_join( WP_CONTENT_DIR, 'fonts' ) . $site_path;
-		$defaults['baseurl'] = untrailingslashit( content_url( 'fonts' ) ) . $site_path;
-		$defaults['error']   = false;
+		$defaults = array(
+			'path'    => path_join( WP_CONTENT_DIR, 'fonts' ) . $site_path,
+			'url'     => untrailingslashit( content_url( 'fonts' ) ) . $site_path,
+			'subdir'  => '',
+			'basedir' => path_join( WP_CONTENT_DIR, 'fonts' ) . $site_path,
+			'baseurl' => untrailingslashit( content_url( 'fonts' ) ) . $site_path,
+			'error'   => false,
+		);
 
 		/**
 		 * Filters the fonts directory data.