A flaw was found in the mod_proxy_cluster in the Apache server. This issue may allow a malicious user to add a script in the 'alias' parameter in the URL to trigger the stored cross-site scripting (XSS) vulnerability. By adding a script on the alias parameter on the URL, it adds a new virtual host and adds the script to the cluster-manager page. The impact of this vulnerability is considered as Low, as the cluster_manager URL should not be exposed outside and is protected by user/password.