diff --git a/wp-includes/embed.php b/wp-includes/embed.php
index ddd5dd988c..b987649f52 100644
--- a/wp-includes/embed.php
+++ b/wp-includes/embed.php
@@ -226,7 +226,7 @@ function wp_maybe_load_embeds() {
  */
 function wp_embed_handler_youtube( $matches, $attr, $url, $rawattr ) {
 	global $wp_embed;
-	$embed = $wp_embed->autoembed( "https://youtube.com/watch?v={$matches[2]}" );
+	$embed = $wp_embed->autoembed( sprintf( "https://youtube.com/watch?v=%s", urlencode( $matches[2] ) ) );
 
 	/**
 	 * Filters the YoutTube embed output.
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 6c70cb9e25..6d8df82197 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7.3-RC1-40149';
+$wp_version = '4.7.3-RC1-40161';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.