diff --git a/wp-includes/http.php b/wp-includes/http.php
index 02b653f5a4..0645bb861e 100644
--- a/wp-includes/http.php
+++ b/wp-includes/http.php
@@ -475,7 +475,7 @@ function wp_http_validate_url( $url ) {
 		}
 		if ( $ip ) {
 			$parts = array_map( 'intval', explode( '.', $ip ) );
-			if ( 127 === $parts[0] || 10 === $parts[0]
+			if ( 127 === $parts[0] || 10 === $parts[0] || 0 === $parts[0]
 				|| ( 172 === $parts[0] && 16 <= $parts[1] && 31 >= $parts[1] )
 				|| ( 192 === $parts[0] && 168 === $parts[1] )
 			) {