Index: wp-includes/class-phpass.php
===================================================================
--- wp-includes/class-phpass.php	(revision 11901)
+++ wp-includes/class-phpass.php	(working copy)
@@ -56,7 +56,7 @@
 	function get_random_bytes($count)
 	{
 		$output = '';
-		if (($fh = @fopen('/dev/urandom', 'rb'))) {
+		if (is_readable('/dev/urandom') && ($fh = @fopen('/dev/urandom', 'rb'))) {
 			$output = fread($fh, $count);
 			fclose($fh);
 		}