diff --git a/wp-includes/kses.php b/wp-includes/kses.php
index 0ef5803ebc..cd30d845f8 100644
--- a/wp-includes/kses.php
+++ b/wp-includes/kses.php
@@ -2526,6 +2526,7 @@ function safecss_filter_attr( $css, $deprecated = '' ) {
 			'list-style-type',
 			'object-fit',
 			'object-position',
+			'opacity',
 			'overflow',
 			'vertical-align',
 			'writing-mode',
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 92f6ddcde5..c555793a5c 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.7-alpha-58708';
+$wp_version = '6.7-alpha-58709';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.