Newsletter vulnerabilities

The Newsletter – Send awesome emails from WordPress plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'nn' parameter in all versions up to, and including, 9.3.8 due to insufficient input sanitization and output escaping. Unauthenticated attackers can inject arbitrary web scripts if they trick a user into clicking a link.

The Newsletter WordPress plugin before 9.3.7 does not validate the destination of the redirect performed after a public subscription action. Unauthenticated attackers can redirect users to arbitrary external sites and disclose a subscriber token that grants access to that subscriber record's front-end actions.

Unauthenticated Cross Site Scripting (XSS) vulnerability in Newsletter plugin versions up to 9.3.3. An attacker can inject malicious script without authentication.