diff --git a/wp-includes/class-wp-theme-json.php b/wp-includes/class-wp-theme-json.php
index d4b50cd953..d4a4fda6a6 100644
--- a/wp-includes/class-wp-theme-json.php
+++ b/wp-includes/class-wp-theme-json.php
@@ -2821,6 +2821,7 @@ class WP_Theme_JSON {
 	 * Removes insecure data from theme.json.
 	 *
 	 * @since 5.9.0
+	 * @since 6.3.1 Preserves global styles block variations when securing styles.
 	 *
 	 * @param array $theme_json Structure to sanitize.
 	 * @return array Sanitized structure.
@@ -2879,6 +2880,20 @@ class WP_Theme_JSON {
 			if ( ! empty( $output ) ) {
 				_wp_array_set( $sanitized, $metadata['path'], $output );
 			}
+
+			if ( isset( $metadata['variations'] ) ) {
+				foreach ( $metadata['variations'] as $variation ) {
+					$variation_input = _wp_array_get( $theme_json, $variation['path'], array() );
+					if ( empty( $variation_input ) ) {
+						continue;
+					}
+
+					$variation_output = static::remove_insecure_styles( $variation_input );
+					if ( ! empty( $variation_output ) ) {
+						_wp_array_set( $sanitized, $variation['path'], $variation_output );
+					}
+				}
+			}
 		}
 
 		$setting_nodes = static::get_setting_nodes( $theme_json );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 1b43221210..ea0ea564cf 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.4-alpha-56501';
+$wp_version = '6.4-alpha-56502';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.