In the process of testing the Relevanssi WordPress plugin before 4.23.1, a vulnerability was found that allows you to implement Stored XSS on behalf of the Contributor+ by embedding malicious script, which entails account takeover backdoor
The Relevanssi – A Better Search plugin for WordPress is vulnerable to Information Exposure in all versions up to, and including, 4.22.2 (Free) and 2.25.1 (Premium) via the relevanssi_do_query() due to insufficient limitations on the posts that are returned when searching. This makes it possible for unauthenticated attackers to extract potentially sensitive information from password protected posts.
The Relevanssi – A Better Search plugin for WordPress is vulnerable to CSV Injection in all versions up to, and including, 4.22.1. This makes it possible for unauthenticated attackers to embed untrusted input into exported CSV files, which can result in code execution when these files are downloaded and opened on a local system with a vulnerable configuration.
The Relevanssi – A Better Search plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the relevanssi_update_counts() function in all versions up to, and including, 4.22.1. This makes it possible for unauthenticated attackers to execute expensive queries on the application that could lead into DOS.
The Relevanssi – A Better Search plugin for WordPress is vulnerable to unauthorized access of data due to a missing capability check on the relevanssi_export_log_check() function in all versions up to, and including, 4.22.0 (Free) and 2.25.0 (Premium). This makes it possible for unauthenticated attackers to export the query log data. The vendor has indicated that they may look into adding a capability check for proper authorization control, however, this vulnerability is theoretically patched as is.
The Relevanssi WordPress plugin before 4.22.0, Relevanssi Premium WordPress plugin before 2.25.0 allows any unauthenticated user to read draft and private posts via a crafted request
Cross-site scripting (XSS) vulnerability in lib/interface.php of the Relevanssi plugin 4.0.4 for WordPress allows remote attackers to inject arbitrary JavaScript or HTML via the tab GET parameter.
Reflected XSS in Relevanssi Premium version 1.14.8 when using relevanssi_didyoumean() could allow unauthenticated attacker to do almost anything an admin can
Cross-site scripting (XSS) vulnerability in the Relevanssi plugin before 3.3.8 for WordPress allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.