diff --git a/wp-includes/class-http.php b/wp-includes/class-http.php
index 91d06c49ff..50e18f99d6 100644
--- a/wp-includes/class-http.php
+++ b/wp-includes/class-http.php
@@ -121,7 +121,8 @@ class WP_Http {
 
 		if ( $r['reject_unsafe_urls'] )
 			$url = wp_http_validate_url( $url );
-		$url = wp_kses_bad_protocol( $url, array( 'http', 'https', 'ssl' ) );
+		if ( function_exists( 'wp_kses_bad_protocol' ) )
+			$url = wp_kses_bad_protocol( $url, array( 'http', 'https', 'ssl' ) );
 
 		$arrURL = @parse_url( $url );