Ticket #42431: 42431.diff

src/wp-includes/wp-db.php

@@ -1946 +1946 @@
                         // If ext/hash is not present, compat.php's hash_hmac() does not support sha256.
                         $algo = function_exists( 'hash' ) ? 'sha256' : 'sha1';
                         // Old WP installs may not have AUTH_SALT defined.
-                        $salt = defined( 'AUTH_SALT' ) ? AUTH_SALT : (string) rand();
+                        $salt = defined( 'AUTH_SALT' ) && AUTH_SALT ? AUTH_SALT : (string) rand();
 
                         $placeholder = '{' . hash_hmac( $algo, uniqid( $salt, true ), $salt ) . '}';
                 }