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 handlecreatelink() 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 headingtext 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 addqueryarg() and removequeryarg().

The Related Posts plugin before 1.8.2 for WordPress has XSS via addqueryarg() and removequeryarg().

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