diff --git a/wp-includes/formatting.php b/wp-includes/formatting.php
index 36b9470e08..5c75642199 100644
--- a/wp-includes/formatting.php
+++ b/wp-includes/formatting.php
@@ -4202,7 +4202,7 @@ function esc_url( $url, $protocols = null, $_context = 'display' ) {
 		return $url;
 	}
 
-	$url = str_replace( ' ', '%20', $url );
+	$url = str_replace( ' ', '%20', ltrim( $url ) );
 	$url = preg_replace( '|[^a-z0-9-~+_.?#=!&;,/:%@$\|*\'()\[\]\\x80-\\xff]|i', '', $url );
 
 	if ( '' === $url ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 5bc91186aa..c91ef5eb46 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-alpha-45577';
+$wp_version = '5.3-alpha-45578';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.