The Freemius SDK, as used by hundreds of WordPress plugin and theme developers, was vulnerable to Cross-Site Request Forgery and Information disclosure due to missing capability checks and nonce protection on the _get_debug_log, _get_db_option, and the _set_db_option functions in versions up to, and including 2.4.2. Any WordPress plugin or theme running a version of Freemius less than 2.4.3 is vulnerable.

The Newsletter, SMTP, Email marketing and Subscribe forms by Brevo (formely Sendinblue) plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 3.1.87. This is due to missing or incorrect nonce validation on the Init() function. This makes it possible for unauthenticated attackers to log out of a Brevo connection via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in wpdev33 WP Newsletter Subscription allows PHP Local File Inclusion.This issue affects WP Newsletter Subscription: from n/a through 1.1.

Cross-Site Request Forgery (CSRF) vulnerability in Brevo Newsletter, SMTP, Email marketing and Subscribe forms by Sendinblue.This issue affects Newsletter, SMTP, Email marketing and Subscribe forms by Sendinblue: from n/a through 3.1.82.

Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Sender Sender – Newsletter, SMS and Email Marketing Automation for WooCommerce allows Reflected XSS.This issue affects Sender – Newsletter, SMS and Email Marketing Automation for WooCommerce: from n/a through 2.6.14.

Server-Side Request Forgery (SSRF) vulnerability in Blossom Themes BlossomThemes Email Newsletter.This issue affects BlossomThemes Email Newsletter: from n/a through 2.2.6.

The ConvertKit – Email Newsletter, Email Marketing, Subscribers and Landing Pages plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the tag_subscriber function in all versions up to, and including, 2.4.9. This makes it possible for unauthenticated attackers to subscribe users to tags. Financial damages may occur to site owners if their API quota is exceeded.

The ConvertKit – Email Newsletter, Email Marketing, Subscribers and Landing Pages plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the tag_subscriber function in all versions up to, and including, 2.4.9. This makes it possible for unauthenticated attackers to subscribe users to tags. Financial damages may occur to site owners if their API quota is exceeded.

The Newsletter - API v1 and v2 addon plugin for WordPress is vulnerable to unauthorized subscribers management due to PHP type juggling issue on the check_api_key function in all versions up to, and including, 2.4.5. This makes it possible for unauthenticated attackers to list, create or delete newsletter subscribers. This issue affects only sites running the PHP version below 8.0

The Newsletter plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'np1' parameter in all versions up to, and including, 8.3.4 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.