This is a new, serious vulnerability, announced recently which has the potential to cause some damage and disruption. Current versions of WordPress are vulnerable to a stored XSS. An unauthenticated attacker can inject JavaScript in WordPress comments. The script is triggered when the comment is viewed. Impact: If triggered by a logged-in administrator, under default settings the attacker can leverage the vulnerability to execute arbitrary code on the server via the plugin and theme editors.
Alternatively the attacker could change the administrator’s password, create new administrator accounts, or do whatever else the currently logged-in administrator can do on the target system. You can find more details about the impact and solution for the same by clicking here.
Steps you need to take: We would request you to go through the recommendations and update your Wordpress website using the patch available here.