diff --git a/wp-includes/rest-api.php b/wp-includes/rest-api.php
index 6c2e7b693b..cc600789f0 100644
--- a/wp-includes/rest-api.php
+++ b/wp-includes/rest-api.php
@@ -1382,6 +1382,14 @@ function rest_validate_value_from_schema( $value, $args, $param = '' ) {
 				)
 			);
 		}
+
+		if ( isset( $args['pattern'] ) ) {
+			$pattern = str_replace( '#', '\\#', $args['pattern'] );
+			if ( ! preg_match( '#' . $pattern . '#u', $value ) ) {
+				/* translators: 1: Parameter, 2: Pattern. */
+				return new WP_Error( 'rest_invalid_pattern', sprintf( __( '%1$s does not match pattern %2$s.' ), $param, $args['pattern'] ) );
+			}
+		}
 	}
 
 	if ( isset( $args['format'] ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 306cf73786..f4866c9dee 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-alpha-47809';
+$wp_version = '5.5-alpha-47810';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.