wpDiscuz before 7.6.47 contains a missing rate limiting vulnerability that allows unauthenticated attackers to subscribe arbitrary email addresses to post notifications by sending POST requests to the wpdAddSubscription handler in class.WpdiscuzHelperAjax.php. Attackers can exploit LIKE wildcard characters in the subscription query to match multiple email addresses and generate unwanted notification emails to victim accounts.
Weakness
The product does not properly limit the number or frequency of interactions that it has with an actor, such as the number of incoming requests.