The Related Posts for WordPress plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.2.1. This is due to missing or incorrect nonce validation on the handle_create_link() function. This makes it possible for unauthenticated attackers to add related posts to other posts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link. This ultimately makes it possible for attackers to view draft and password protected posts.

Auth. (admin+) Stored Cross-Site Scripting (XSS) vulnerability in Never5 Post Connector plugin <= 1.0.9 versions.

Cross-site Scripting (XSS) - Stored in GitHub repository barrykooij/related-posts-for-wp prior to 2.1.3.

The Related Posts for WordPress plugin through 2.0.4 does not sanitise its heading_text and CSS settings, allowing high privilege users (admin) to set XSS payloads in them, leading to Stored Cross-Site Scripting issues.

Unvalidated input and lack of output encoding within the Related Posts for WordPress plugin before 2.0.4 lead to a Reflected Cross-Site Scripting (XSS) vulnerability within the 'lang' GET parameter while editing a post, triggered when users with the capability of editing posts access a malicious URL.

The Post Connector plugin before 1.0.4 for WordPress has XSS via add_query_arg() and remove_query_arg().

The Related Posts plugin before 1.8.2 for WordPress has XSS via add_query_arg() and remove_query_arg().

The download-monitor plugin before 1.7.1 for WordPress has XSS related to add_query_arg.