SlimStat Analytics WordPress Plugin Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the SlimStat Analytics plugin for WordPress, affecting all versions through 5.3.5. The issue arises from inadequate input sanitization and output escaping, allowing unauthenticated attackers to inject arbitrary web scripts via the 'fh' (fingerprint) parameter. These scripts are executed when a user accesses the compromised page.

Impact

Exploitation of this vulnerability allows for stored cross-site scripting, where injected scripts are executed in the context of the user viewing the page.

Reproduction

The vulnerability can be reproduced by sending a request to a WordPress site with the SlimStat Analytics plugin installed, using the 'fh' parameter to inject a script. This can be done through the WordPress REST API or by manipulating the JavaScript tracker that the plugin uses.

Remediation

Users are advised to update the SlimStat Analytics plugin to version 5.4.0 or later.