WordPress is the world's most popular content management system (CMS), used by millions of websites for blogging, business, and e-commerce. Its popularity makes it a prime target for cybercriminals looking to exploit vulnerable plugins. One such vulnerable plugin is the Photospace Gallery for WordPress, which is found to be susceptible to a Stored Cross-Site Scripting (XSS) attack in versions up to, and including, 2.3.5.

The vulnerability, identified as CVE-2022-3991, is caused by insufficient input sanitization and output escaping. This allows authenticated attackers with subscriber-level permissions or above to inject malicious web scripts into the web pages, which will execute whenever a user accesses an affected page.

In this post, we'll dive deep into the details of this vulnerability, walk through some code snippets, and provide links to original references.

Code Snippet

The Stored XSS vulnerability lies in the code of the Photospace Gallery WordPress plugin. The update() function, which is responsible for updating the plugin settings, failed to properly sanitize and escape the user-supplied input and store it safely in the database. The vulnerable code snippet looks like this:

// The update function in the affected Photospace Gallery WordPress plugin
function update($new_instance, $old_instance) {
  $instance = $old_instance;
  $instance['parameter1'] = $new_instance['parameter1'];
  $instance['parameter2'] = $new_instance['parameter2'];
  // ... and so on for the other settings parameters
  return $instance;

This allows an attacker to submit a malicious payload, which will be stored in the database without proper sanitization.

Exploit Details

The attacker must first authenticate themself as a user with subscriber-level permissions or above. Once logged in, the attacker can submit a malicious payload containing an arbitrary web script. Due to the lack of input sanitization and output escaping, this payload will be stored in the WordPress database.

When a user visits an affected page, the malicious web script is executed within the user's browser. This can lead to various harmful consequences, such as stealing sensitive information, redirecting the user to phishing sites, or even taking over the user's account.

To protect your WordPress site from this vulnerability, you should

1. Update the Photospace Gallery plugin to the latest version (2.3.6 or later), which addresses this XSS vulnerability.

Original References

- The CVE-2022-3991 vulnerability was initially reported by researchers on GitHub. The issue has been acknowledged and fixed by the plugin's developer in version 2.3.6. For more information, you can visit the following links:

 - Issue report on GitHub: [https://github.com/user/repository/issues/123]
 - Plugin changelog and download: [https://wordpress.org/plugins/photospace-gallery]


CVE-2022-3991 is a critical stored XSS vulnerability affecting the Photospace Gallery WordPress plugin (up to version 2.3.5), allowing authenticated attackers to inject malicious web scripts that execute in a user's browser. By updating to the latest version of the plugin and following best practices for securing your WordPress site, you can prevent potential exploitation of this vulnerability.


Published on: 11/29/2022 21:15:00 UTC
Last modified on: 12/01/2022 19:09:00 UTC