RevInsite Plugin Under Attack: Stored XSS Vulnerability Uncovered (CVE-2025-13863)

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Overview

CVE-2025-13863 identifies a Stored Cross-Site Scripting (XSS) vulnerability present in the RevInsite plugin for WordPress. This vulnerability affects all versions up to, and including, 1.1.0. It allows authenticated attackers with Contributor-level access or higher to inject malicious JavaScript code into pages via the vulnerable `token` parameter. When a user visits a page containing the injected script, the script will execute within their browser context, potentially leading to data theft, session hijacking, or other malicious activities.

Technical Details

The vulnerability stems from insufficient input sanitization and output escaping within the RevInsite plugin’s code. Specifically, the `token` parameter is not properly validated before being stored in the database, and it is not correctly escaped when displayed on a page. This allows an attacker to inject arbitrary HTML and JavaScript code. The vulnerable code is located, for example, around line 25 in the `revinsite.php` file.

An attacker can exploit this by crafting a malicious request containing a payload in the `token` parameter. This request can be sent while authenticated as a Contributor or a higher-level user. The payload will then be stored in the database and executed when the affected page is loaded by another user (including administrators).

Example Attack Vector:

            POST /wp-admin/admin-post.php HTTP/1.1
            Host: example.com
            Cookie: [WordPress authentication cookies]
            Content-Type: application/x-www-form-urlencoded

            action=revinsite_settings&token=<script>alert('XSS Vulnerability!')</script>&submit=Save

CVSS Analysis

The Common Vulnerability Scoring System (CVSS) assigns CVE-2025-13863 a score of 6.4 (Medium).

  • Vector String: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
  • Explanation: This score reflects the network attack vector (AV:N), low attack complexity (AC:L), the requirement for low privileges (PR:L) – Contributor role, user interaction (UI:R) – victim needs to visit the crafted page, a changed scope (S:C) indicating the injected script executes in a different security context, and low impact to confidentiality (C:L) and integrity (I:L) with no impact to availability (A:N).

Possible Impact

A successful exploitation of this vulnerability can have significant consequences:

  • Account Takeover: An attacker could steal administrator cookies, leading to complete control of the WordPress site.
  • Malware Distribution: The injected script could redirect users to malicious websites or silently download malware onto their computers.
  • Defacement: The attacker could modify the appearance of the website or inject unwanted content.
  • Data Theft: Sensitive information displayed on the affected pages could be stolen.

Mitigation and Patch Steps

The recommended mitigation is to update the RevInsite plugin to a version that addresses this vulnerability. Check the WordPress plugin repository or the developer’s website for an updated version. If an update is not yet available, consider temporarily disabling the plugin until a patch is released.

If you cannot immediately update or disable the plugin, you can attempt to mitigate the vulnerability by:

  • Limiting User Roles: Restrict contributor-level access to only trusted users.
  • Implementing a Web Application Firewall (WAF): A WAF can help detect and block malicious requests targeting the `token` parameter.

References

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