Newsletters WordPress plugin vulnerabilities

The Newsletters WordPress plugin before 4.18.1 does not perform an ownership check on some of its subscriber management actions, and issues a management session to unauthenticated visitors on request. This allows attackers to read any subscriber's personal data and overwrite any subscriber's record, including their email address.

The Newsletters WordPress plugin before 4.16 does not authenticate or validate a bounce-processing request before fetching a user-supplied URL on the server side. This allows unauthenticated attackers to make the site issue requests to arbitrary internal or external hosts.

The Newsletters WordPress plugin before version 4.15 fails to prevent deserialization of untrusted input submitted via a public form. This allows unauthenticated attackers to inject a PHP object and, through a property-oriented gadget chain, write arbitrary files and execute code on the server.