Overview
CVE-2025-66309 identifies a Reflected Cross-Site Scripting (XSS) vulnerability in the Grav Admin Plugin, a popular tool used for managing Grav CMS installations. Specifically, the vulnerability affects versions prior to 1.11.0-beta.1. This flaw allows attackers to inject malicious JavaScript code into user sessions via a crafted URL. It’s crucial to update your Grav Admin Plugin to version 1.11.0-beta.1 or later to mitigate this risk.
Technical Details
The vulnerability resides within the /admin/pages/[page] endpoint of the Grav application. An attacker can inject malicious scripts through the data[header][content][items] parameter. When a Grav administrator accesses a specially crafted URL, the injected script is executed within their browser context. This allows the attacker to potentially steal cookies, redirect the user, or perform other malicious actions on behalf of the administrator.
Example vulnerable URL (Illustrative – Do NOT execute in a production environment):
/admin/pages/somepage?data[header][content][items]=<script>alert('XSS Vulnerability')</script>
CVSS Analysis
Currently, the severity and CVSS score for CVE-2025-66309 are marked as N/A. However, XSS vulnerabilities can pose a significant threat, particularly in administrative interfaces. Given the ability to compromise administrator accounts, a high severity rating would be expected once a complete CVSS analysis is performed.
Possible Impact
Successful exploitation of this XSS vulnerability could lead to several severe consequences:
- Administrator Account Takeover: Attackers can steal administrator cookies and hijack their sessions, gaining full control over the Grav CMS.
- Website Defacement: Attackers can inject malicious content into the website, defacing it or spreading malware.
- Data Theft: Attackers can steal sensitive data stored within the Grav CMS, including user credentials and confidential information.
- Redirection to Malicious Sites: Users can be redirected to phishing sites or other malicious websites, leading to further compromise.
Mitigation and Patch Steps
The recommended mitigation is to upgrade the Grav Admin Plugin to version 1.11.0-beta.1 or later. This version contains a fix that prevents the injection of malicious scripts via the data[header][content][items] parameter.
- Backup Your Grav Installation: Before performing any updates, create a full backup of your Grav CMS installation, including the database and all files.
- Access the Grav Admin Panel: Log in to your Grav admin panel.
- Update the Admin Plugin: Navigate to the Plugins section and update the Admin plugin to the latest available version (at least 1.11.0-beta.1).
- Verify the Update: After the update is complete, verify that the Admin plugin version is 1.11.0-beta.1 or higher.
- Test Your Website: After updating, thoroughly test your website to ensure that everything is functioning correctly.
