The Relevanssi – A Better Search plugin for WordPress is vulnerable to Reflected Cross-Site Scripting in versions up to, and including, 4.28.1 via the 's', 'posttypes', and 'orderby' request parameters. This is due to insufficient input sanitization and output escaping in the relevanssidebugarray() function in lib/debug.php, which dumps user-supplied query variables through printr() inside a <pre> block without HTML escaping. The debug path is enabled by supplying the relevanssidebug=on request parameter when the administrator has previously enabled the 'Debugging mode' setting; the gate itself is a configuration check with no capability, nonce, or logged-in check (the vendor explicitly suppresses nonce verification on that line). This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a specially crafted link.

The Relevanssi – A Better Search plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Excerpt Highlights in all versions up to, and including, 4.24.5 (Free) and 2.27.6 (Premium) 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.

The Relevanssi – A Better Search plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the highlights functionality in all versions up to, and including, 4.24.3 (Free) and <= 2.27.4 (Premium), 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 via the search results.

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 Live Ajax Search plugin for WordPress is vulnerable to argument injection in all versions up to, and including, 2.4. This is due to insufficient validation of input supplied via POST data in the 'search' function. This makes it possible for unauthenticated attackers to inject arbitrary arguments into a WPQuery query and potentially expose sensitive information such as attachments or private posts.

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 relevanssidoquery() 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 unauthorized modification of data due to a missing capability check on the relevanssiupdatecounts() 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 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 access of data due to a missing capability check on the relevanssiexportlogcheck() 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

The Relevanssi Premium plugin before 1.14.6.1 for WordPress has SQL injection with resultant unsafe unserialization.

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 relevanssididyoumean() could allow unauthenticated attacker to do almost anything an admin can

WordPress plugin Relevanssi version 3.5.7.1 is vulnerable to stored XSS resulting in attacker being able to execute JavaScript on the affected site

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.