diff --git a/wp-includes/class-wp-customize-manager.php b/wp-includes/class-wp-customize-manager.php
index bb892b564e..23e319167e 100644
--- a/wp-includes/class-wp-customize-manager.php
+++ b/wp-includes/class-wp-customize-manager.php
@@ -1003,6 +1003,13 @@ final class WP_Customize_Manager {
 				continue;
 			}
 			$validity = $setting->validate( $unsanitized_value );
+			if ( ! is_wp_error( $validity ) ) {
+				/** This filter is documented in wp-includes/class-wp-customize-setting.php */
+				$late_validity = apply_filters( "customize_validate_{$setting->id}", new WP_Error(), $unsanitized_value, $setting );
+				if ( ! empty( $late_validity->errors ) ) {
+					$validity = $late_validity;
+				}
+			}
 			if ( ! is_wp_error( $validity ) ) {
 				$value = $setting->sanitize( $unsanitized_value );
 				if ( is_null( $value ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 2e35c2bf2c..3a45604f45 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38764';
+$wp_version = '4.7-alpha-38765';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.